A   B   C   D   E   F   G   H   I   K   L   M   N   O   P   Q   R   S   T   U   V   W  

focusing

Paper Title Other Keywords Page
MOPC014 Optimization of the Focusing Lattice for European XFEL lattice, simulation, undulator, radiation 97
 
  • V. G. Khachatryan, A. Tarloyan, V. M. Tsakanov
    CANDLE, Yerevan
  • W. Decking
    DESY, Hamburg
  • V. V. Sahakyan
    YSU, Yerevan
  Detailed knowledge of the impact of the undulator section focusing lattice on the FEL performance is an important issue to ensure the stable operation of the facility with reliable tolerances. In this paper the results of numerical simulation studies for the European XFEL project are presented. The saturation length, saturation power and the spectral brightness of the SASE FEL are calculated for various focusing lattice arrangements. A focusing optics option with reduced number of FODO cells is discussed to reach the design goals with relaxed quadrupole magnet tolerances. The numerical simulations are performed using the SIMPLEX and GENESIS codes.  
 
MOPD023 Parametric Study of a Novel Coaxial Bunched Beam Space-charge Limit space-charge, electron, plasma, klystron 493
 
  • M. Hess
    IUCF, Bloomington, Indiana
  Recently, a non-trivial space-charge limit for off-axis bunched electron beams in a coaxial conducting structure was derived theoretically*. The space-charge limit describes the minimum strength of an external solenoidal focusing field which is needed to stabilize the beam’s center-of-mass motion in the presence of induced surface charges on the coaxial structure. In this paper, we perform a parametric study of the space-charge limit to numerically determine its dependency on the conducting structure geometry, i.e., the ratio of the inner and outer conductor radii, as well as its’ dependency on the transverse and longitudinal bunch distributions. As an application, we show how this parametric study can be important for the design of high-power microwave sources, such as the UC-Davis/SLAC 2.8 GHz coaxial ubitron oscillator**.

*M. Hess, accepted for publication in IEEE Trans. Plasma Sci. (2008).
**A. J. Balkcum et al. IEEE Trans. Plasma Sci., vol. 26, pp. 548-555, 1998.

 
 
MOPD035 20 MW Pulse Amplifier Klystron with Multiple Frequency Two-Gap Bunching Resonators for Linear Electron Accelerators klystron, electron, bunching, vacuum 529
 
  • K. G. Simonov, A. N. Korolev, A. V. Mamontov
    ISTOK, Moscow Region
  A klystron design with a two-gap bunching resonator which provides interaction with electron beam by fields of multiple frequencies of two-gap resonator fundamental oscillations for increasing the klystron efficiency is being considered. At that the two-gap resonator is tuned to antiphased oscillation at operating frequency and to in-phase oscillation at the second harmonic. Such choice of frequency oscillation types allows to make the resonator compact and provide optimal conditions for electron beam interaction with microwave fields of the two-gap resonator both in antiphased and in-phase oscillation types. The relations for choosing two-gap resonator interaction area size providing a stable klystron operation without self-excitation are given. The compactness of the realized two-gap resonator with multiple frequencies allowed to locate it into klystron drift tube between the main resonators without increasing the klystron overall dimensions. The results of experimental research of klystron with such a two-gap resonator showed a possibility to increase its efficiency significantly.  
 
MOPP013 Coupler Kick for Very Short Bunches and its Compensation emittance, betatron, laser, radio-frequency 580
 
  • M. Dohlus, I. Zagorodnov
    DESY, Hamburg
  • E. Gjonaj, T. Weiland
    TEMF, Darmstadt
  In this contribution we estimate two different effects: the kick due to asymmetry of the external accelerating field (coupler RF kick) and the kick due to electromagnetic field of the bunch scattered by the couplers (coupler wake kick). We take into acoount the cavities and calculate the periodic solution for bunch with an rms width of 300 mkm. The different possibilities for compensation of the kick are considered.  
 
MOPP036 Dark Current Model for ILC Main Linac linac, simulation, electron, quadrupole 625
 
  • N. Solyak, N. V. Mokhov, G. V. Romanov
    Fermilab, Batavia, Illinois
  • Y. I. Eidelman
    BINP SB RAS, Novosibirsk
  • W. M. Tam
    IUCF, Bloomington, Indiana
  In the ILC Main Linac the dark current electrons, generated in SRF cavity can be accelerated to hundreds of MeV before being kicked out by quadrupoles and thus will originate electromagnetic cascade showers in the surrounding materials. Some of the shower secondaries can return back into vacuum and re-accelerated again. The results of simulation of the dark current dynamics and energy deposition along the linac are discussed in paper.  
 
MOPP042 RF Kick in the ILC Acceleration Structure emittance, linac, acceleration, alignment 637
 
  • V. P. Yakovlev, I. G. Gonin, A. Latina, A. Lunin, K. Ranjan, N. Solyak
    Fermilab, Batavia, Illinois
  Detailed results of estimations and simulations for the RF kick caused by input and HOM couplers of the ILC acceleration structure are presented. Results of possible beam emittance dilution caused by RF kick are discussed for the main LINAC acceleration structure, and the RF structures of the ILC bunch compressors BC1 and BC2. Methods of the RF kick reduction are discussed.  
 
MOPP062 Optics Design Considerations for the CLIC Pre-damping Rings emittance, quadrupole, optics, damping 685
 
  • Y. Papaphilippou
    CERN, Geneva
  • F. Antoniou
    National Technical University of Athens, Zografou
  The CLIC pre-damping rings have to accommodate a large emittance beam, coming in particular from the positron source and reduce its size to low enough values for injection into the main damping rings. Linear lattice design options based on an analytical approach for theoretical minimum emittance cells are presented. In particular the parameterisation of the quadrupole strengths and optics functions with respect to the emittance and drift lengths is derived. Complementary considerations regarding constraints imposed by positron stacking and input momentum spread are also considered.  
 
MOPP073 Plasma Lens for Muon and Neutrino Beams plasma, target, proton, simulation 718
 
  • S. A. Kahn, S. Korenev
    Muons, Inc, Batavia
  • M. B. Bishai, M. Diwan, J. C. Gallardo, A. Hershcovitch, B. M. Johnson
    BNL, Upton, Long Island, New York
  The plasma lens is examined as an alternate to focusing horns and solenoids for use in a neutrino or muon beam facility. The plasma lens concept is based on a combined high current lens/target configuration. The current is fed at electrodes located upstream and downstream form the target where pion capturing is needed. The current flows primarily in the plasma, which has a lower resistivity than the target. A second plasma lens section, with an additional current feed, follows the target to provide shaping of the plasma for optimum focusing. The plasma lens is immersed in an additional solenoidal magnetic field to facilitate the plasma stability. The geometry of the plasma is shaped to provide optimal pion capture. Simulations of this plasma lens system have shown a 25% higher neutrino production than the horn system. Plasma lenses have additional advantages: larger axial currents than horns, minimal neutrino contamination during antineutrino running, and negligible pion absorption or scattering. Results from particle simulations using plasma lens will be presented.  
 
MOPP098 A 201-MHz Normal Conducting RF Cavity for the International MICE Experiment coupling, vacuum, impedance, emittance 784
 
  • D. Li, A. J. DeMello, S. P. Virostek, M. S. Zisman
    LBNL, Berkeley, California
  • R. A. Rimmer
    Jefferson Lab, Newport News, Virginia
  MICE is a demonstration experiment for the ionization cooling of muon beams. Eight RF cavities are proposed to be used in the MICE cooling channel. These cavities will be operated in a strong magnetic field; therefore, they must be normal conducting. The cavity design and construction are based on the successful experience and techniques developed for a 201-MHz prototype cavity for the US MUCOOL program. Taking advantage of a muon beam’s penetration property, the cavity employs a pair of curved thin beryllium windows to terminate conventional beam irises and achieve higher cavity shunt impedance. The cavity resembles a round, closed pillbox cavity. Two half-shells spun from copper sheets are joined by e-beam welding to form the cavity body. There are four ports on the cavity equator for RF couplers, vacuum pumping and field probes. The ports are formed by means of an extruding technique.  
 
TUOBG03 Electron Beam Dynamics in the Long-pulse, High-current DARHT-II Linear Induction Accelerator electron, induction, impedance, dipole 968
 
  • C. Ekdahl, E. O. Abeyta, P. Aragon, R. D. Archuleta, G. V. Cook, D. Dalmas, K. Esquibel, R. J. Gallegos, R. W. Garnett, J. F. Harrison, E. B. Jacquez, J. Johnson, B. T. McCuistian, N. Montoya, S. Nath, K. Nielsen, D. Oro, L. J. Rowton, M. Sanchez, R. D. Scarpetti, M. Schauer, G. J. Seitz, H. V. Smith, R. Temple
    LANL, Los Alamos, New Mexico
  • H. Bender, W. Broste, C. Carlson, D. Frayer, D. Johnson, C.-Y. Tom, C. P. Trainham, J. T. Williams
    NSTec, Los Alamos, New Mexico
  • T. C. Genoni, T. P. Hughes, C. H. Thoma
    Voss Scientific, Albuquerque, New Mexico
  • B. A. Prichard, M. E. Schulze
    SAIC, Los Alamos, New Mexico
  We are now operating the full-scale DARHT-II linear induction accelerator (LIA) at its rated energy, accelerating 2-kA electron beams to more than 17 MeV. The injector produces a beam pulse with a full-width at half maximum (FWHM) greater than 2.5 microseconds, and a ~0.5 microsecond rise time. This long risetime is deliberately scraped off in a special beam-head cleanup zone (BCUZ) before entering the 68-cell main accelerator. The accelerated electron beam pulse has a flat-top region where the final electron kinetic energy varies by less than 1% for more than 1.5 microseconds. We will discuss the tuning of the injector, BCUZ, and accelerator; and we will present data for the resulting beam transport and dynamics. We will also present beam stability data, which we will relate to previous stability experiments at lower current and energy*.

*Carl Ekdahl et al. "Long-pulse beam stability experiments on the DARHT-II linear induction accelerator," IEEE Trans. Plasma. Sci. Vol. 34, 2006, pp. 460-466.

 
slides icon Slides  
 
TUOBM02 The Development of the Separated Function RFQ Accelerator in Peking University rfq, simulation, impedance, acceleration 1007
 
  • X. Q. Yan, J.-E. Chen, J. X. Fang, S. L. Gao, Z. Y. Guo, Y. R. Lu, Z. Wang, K. Zhu
    PKU/IHIP, Beijing
  The progress of the Separated Function RFQ (SFRFQ) accelerator, which can raise the field gradient of acceleration while maintaining the transverse focusing power sufficient for high current beam, is presented. In order to demonstrate the feasibilities of the novel accelerator, a prototype cavity was designed and constructed. Correspondingly, a code SFRFQCODEV1.0 was developed specially for cavity design and beam dynamics simulation. The prototype cavity will be verified as a post-accelerator for ISR RFQ-1000 (Integral Split Ring RFQ) and accelerate O+ from 1 MeV to 1.6 MeV. To inject a higher current oxygen beam for the prototype cavity, the beam current of ISR RFQ-1000 was upgraded to 2 mA. The status of high power and beam test of the prototype cavity are presented in this paper.  
slides icon Slides  
 
TUPC027 Spatial Autocorrelation for Transverse Beam Quality Characterization laser, emittance, space-charge, brightness 1107
 
  • V. Fusco, M. Ferrario
    INFN/LNF, Frascati (Roma)
  • C. Ronsivalle
    ENEA C. R. Frascati, Frascati (Roma)
  Low emittance beams are required for high brightness beams applications. Contributions to emittance degradations come from electromagnetic fields’ non-linearities which can be reduced using a transversally and longitudinally uniform beam. For these reasons the evaluation of the beam quality is a very important task. Concerning the transverse analysis the spatial correlation parameter has been introduced: it gives an evaluation of how beam non-uniformity is distributed. The paper describes the spatial autocorrelation concept and applies it to the evaluation of a laser beam for high brightness beam applications. Moreover the paper shows the spatial autocorrelation evolution along a photo-injector as an additional tool for beam dynamics studies.  
 
TUPC066 Temporal Spot Size Evolution of the DARHT First Axis Radiographic Source ion, electron, target, radiation 1206
 
  • B. T. McCuistian, D. C. Moir, E. A. Rose
    LANL, Los Alamos, New Mexico
  • H. Bender, C. Carlson, C. G. Hollabaugh, R. Trainham
    NSTec, Los Alamos, New Mexico
  DARHT is the Dual Axis Radiographic Hydrodynamic Test Facility at Los Alamos National Laboratory. The radiographic spot size is a critical parameter in the performance of the facility to produce quality radiographs. Time resolved images of the radiographic spot of the First Axis of the DARHT facility have been acquired and correlated with the radiation pulse. Analysis of these time resolved images illustrates the effect of beam target interaction on the temporal evolution of the spot size. An explanation of the experimental setup and analysis of the data will be presented.  
 
TUPD011 The Pulsed Quadrupole Magnet for KEKB Low Energy Ring quadrupole, luminosity, positron, electron 1455
 
  • T. Mimashi, T. Ieiri, M. Kikuchi
    KEK, Ibaraki
  • A. Tokuchi, K. Tsuchida
    Nichicon (Kusatsu) Corporation, Shiga
  In the KEKB low energy ring, because of photoelectron clouds, the betatron tune changes along the position in the train. The produced photoelectron gives focusing force to the beam. It is remarkable especially in the vertical tune. Since we have a 500 nanoseconds beam abort gap, the photoelectron focusing force is weaker at the head of train. It means the vertical tune is lower at the head of the train. In order to cancel this tune shift, the pulsed quadrupole magnet was installed. The pulsed quadrupole magnet system and its performance are described.  
 
TUPD039 Load Curves Distortion Induced by Fringe Field Effects in the Ion Nanoprobe quadrupole, ion, controls 1514
 
  • Yu. V. Tereshonkov, S. N. Andrianov
    St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
  Nanoprobes are known to be high precision systems, which require preliminary modeling for thorough analysis of optimal working modes. One of most crucial characteristics of the special class of such beam lines is the so-called load curves (or surfaces). This paper investigates one of the types of intrinsic effects, i.e. fringe fields and their influence on load curves and surfaces, which make it possible to construct the purposeful search of optimal working regimes for nanoprobes. A number of different models for fringe field presentation are discussed in the paper. Analytical and numerical methods and tools are used for analysis and selection of optimal parameters for fringe field models.  
 
TUPP045 Studies of Beam Breakup in Dielectric Structures simulation, quadrupole, single-bunch, electron 1643
 
  • A. Kanareykin, C.-J. Jing, A. L. Kustov, P. Schoessow
    Euclid TechLabs, LLC, Solon, Ohio
  • W. Gai, J. G. Power
    ANL, Argonne, Illinois
  Beam breakup (BBU) effects resulting from parasitic wakefields provide a potentially serious limitation to the performance of dielectric structure based wakefield accelerators. We report on experimental and numerical investigation of BBU and its mitigation. The experimental program focuses on BBU measurements in a number of high gradient and high transformer ratio wakefield devices. New pickup-based beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable at the AWA facility. The numerical part of this research is based on a particle-Green’s function beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the results of detailed experimental measurements with the accurate numerical results and to design an external FODO channel for the control of the beam in the presence of strong transverse wakefields.  
 
TUPP089 Implementation of Fringe Field Dipole Magnets into the V-Code Beam Dynamics Simulation Tool simulation, dipole, multipole, vacuum 1738
 
  • S. S. Franke, W. Ackermann, B. Steiner, T. Weiland
    TEMF, Darmstadt
  • J. Enders, C. Hessler, Y. Poltoratska
    TU Darmstadt, Darmstadt
  Fast online beam dynamics simulations can advantageously assist the machine operators at various particle accelerator machines because they provide a more detailed insight into the actual machine status. Based on the moment approach a fast tracking code named V-Code has been implemented at TEMF. Within the SFB 634 project the V-Code beam dynamics simulation tool is supposed to be installed at the Superconducting Darmstadt LINear ACcelerator S-DALINAC which is designed as a re-circulating linear accelerator. In order to be able to simulate the entire beam line, an implementation of fringe field dipole magnets is mandatory. Unlike a hard edged field approach the fringe fields influence the beam focusing and its inhomogeneity results in a non-circular bunch motion. For an accurate reproduction of the transverse motion specialized techniques to obtain and to handle the reference path in V-Code together with the 3D-field data along the curved trajectory had to be developed. In the paper a summary of implementation details together with simulation results will be provided.  
 
TUPP099 Improvement of RFQSIM rfq, simulation, acceleration, multipole 1762
 
  • J. M. Maus, A. Schempp
    IAP, Frankfurt am Main
  RFQSIM has constantly been developed at IAP to simulate multiple particles dynamic of RFQs which include simulations of high current applications, decelerators, debuncher and rebuncher e.g. for the medical application. The latest work to improve RFQSIM include the option to change the modulation and or the aperatur of the simulated RFQ to produce the same acceleration and or focusing efficiency than the two term potential gives for different electrode geometries. Additional work was done to improve the graphical analysis during runtime as well as the change of all routines to be compatible with the Fortran F95 standard. The maximum number of particles to be simulated was increased to 200k. The paper shows examples of results for the high current application like the of the p-linac and the new HLI injector for GSI and for transition sections.  
 
TUPP150 The Radiatron: A High Average Current Betatron for Industrial and Security Applications betatron, acceleration, electron, injection 1860
 
  • S. Boucher, R. B. Agustsson, P. Frigola, A. Y. Murokh, M. Ruelas
    RadiaBeam, Los Angeles
  • F. H. O'Shea, J. B. Rosenzweig, G. Travish
    UCLA, Los Angeles, California
  The fixed-field alternating-gradient (FFAG) betatron has emerged as a viable alternative to RF linacs as a source of high-energy radiation for industrial and security applications. For industrial applications, high average currents at modest relativistic electron beam energies, typically in the 5 to 10 MeV range, are desired for medical product sterilization, food irradiation and materials processing. For security applications, high power x-rays in the 3 to 20 MeV range are needed for rapid screening of cargo containers and vehicles. In a FFAG betatron, high-power output is possible due to high duty factor and fast acceleration cycle: electrons are injected and accelerated in a quasi-CW mode while being confined and focused in the fixed-field alternating-gradient lattice. The beam is accelerated via magnetic induction from a betatron core made with modern low-loss magnetic materials. Here we present the design and status of a prototype FFAG betatron, called the RadiaTron, as well as future prospects for these machines.  
 
TUPP161 60 keV 30 kW Electron Beam Facility for Electron Beam Technology electron, controls, cathode, gun 1887
 
  • Yu. I. Semenov, V. E. Akimov, M. A. Batazova, B. A. Dovzhenko, V. V. Ershov, A. R. Frolov, I. A. Gusev, Ye. A. Gusev, V. M. Konstantinov, N. Kh. Kot, V. R. Kozak, E. A. Kuper, G. I. Kuznetsov, P. V. Logatchev, V. R. Mamkin, A. S. Medvedko, I. V. Nikolaev, A. Yu. Protopopov, D. N. Pureskin, V. V. Repkov, A. N. Selivanov, D. V. Senkov, A. S. Tsyganov, A. A. Zharikov
    BINP SB RAS, Novosibirsk
  At the Budker Institute of Nuclear Physics, Novosibirsk, the 60 keV 30 kW electron beam facility for electron beam technology has been developed. The electron gun provides continuous or modulated beam within the current range from 1 mA up to 500 mA. The optical system allows both static and dynamic focusing of the electron beam within the 50/500 mm range of distance from the gun outlet, the beam scanning and its parallel displacement from the optical axis. The electron gun facility is controlled by the computer via the CAN interface. This paper presents the general description of the facility, its block diagram and main parameters.  
 
WEPC013 Commissioning of Medium Emittance Lattice of HLS Storage Ring emittance, radiation, brilliance, lattice 2013
 
  • G. Feng, W. Li, L. Liu, L. Wang, H. Xu, S. C. Zhang
    USTC/NSRL, Hefei, Anhui
  Hefei Light Source (HLS) is a second generation light source, whose emittance is about 160 nmrad in normal optics. Lowering beam emittance is the most effective measure to enhance light source brilliance. Considering beam lifetime limitation, a lattice with medium beam emittance was brought forward. Through distributed dispersion in straight section, the beam emittance was reduced to 80 nmrad. At same time, the betatron tunes were kept same as before. In this way, the focusing parameters can be tuned to new one smoothly. With the new lattice parameters, the brilliance of HLS is increased by two factors.  
 
WEPC048 Experimental Characterization of the Insertion Device Effects on Beam Dynamics at SOLEIL undulator, injection, coupling, insertion 2097
 
  • P. Brunelle, C. Benabderrahmane, F. Briquez, O. V. Chubar, O. Marcouillé, F. Marteau, A. Nadji, L. S. Nadolski
    SOLEIL, Gif-sur-Yvette
  SOLEIL, the French 2.75 GeV third generation light source, has been delivering photons to beam lines in routine operation since January 2007. The storage ring is presently equipped with eleven insertion devices: 3 in-vacuum 20mm period undulators (U20), 1 Apple-II type 52mm period undulator (HU52), 3 Apple-II type 80mm period undulators (HU80), 3 electromagnetic 256mm period undulators (HU256) and 1 electromagnetic 640mm period 10m long undulator (HU640). Commissioning of insertion devices consists of characterizing all the effects on beam dynamics in terms of focussing, injection efficiency, beam lifetime and sensitivity to working point, and also in optimizing feedforward tables in order to compensate for closed orbit distortions during field variations (this last point is detailed in other papers). We will focus here on the significant effects observed with some undulators. Measurements, using electron beam, of the transverse variation of field integrals, were helpful to understand bad effects impacting the daily operation. The introduction of real magnetic characteristics in the lattice model is in progress in order to further optimize the working point.  
 
WEPC085 Matching with Space Charge space-charge, quadrupole, diagnostics, emittance 2192
 
  • B. D. Muratori, D. J. Holder
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  This paper explores the possibility of performing matching in the presence of space charge to an acceptable and useful level. Space charge gives rise to a mismatch for beams at low energies. This mismatch can be very harmful for certain applications, for example the tomography diagnostic of the PITZ2 test line. In this case, the Twiss parameters at the start of the tomography section have to be as close as possible to the design ones. As can be shown by a thin lens approximation, all the Twiss parameters at the start of the tomography section are fully determined, as is the quadrupole strength, once the length of the FODO cells is chosen. With the presence of space charge it is necessary to introduce a modification to the original matching, itself performed with a standard optimizing routine. The idea is that this modification can only compensate for the linear part of space charge and it does so by changing the quadrupole strengths. The theory is verified by using an very simple test line consisting of just two quadrupoles and modeling it using GPT (General Particle Tracer). This results in modified values for the quadrupole strengths to accommodate the effect of space charge.  
 
WEPC107 Observation and Interpretation of Dynamic Focusing Effects Introduced by APPLE-II Undulators on Electron Beam at SOLEIL undulator, electron, betatron, storage-ring 2249
 
  • O. V. Chubar, P. Brunelle, M.-E. Couprie, J.-M. Filhol, A. Nadji, L. S. Nadolski
    SOLEIL, Gif-sur-Yvette
  The paper presents the results of electron beam closed orbit distortion (COD) and tune shift measurements performed on three different APPLE-II type undulators when making horizontal displacements of the electron beam orbit in those straight sections of the SOLEIL storage ring where these undulators are installed. In agreement with data from other storage rings, our results show that, when APPLE-II undulators are used in elliptical, linear-vertical or linear-tilted polarization modes, the measured tune shifts and the COD can not be explained only by residual first-order focusing effects: taking into account the second-order, or dynamic focusing effects, is necessary. We describe a COD interpretation method allowing for straightforward comparison of the measured effects on electron beam with the corresponding predictions from calculations and magnetic measurements. The observed dynamic effects are in good agreement with calculations performed using RADIA code. We also discuss possible modification of the figures of merit to be used at computer-aided shimming of APPLE-II undulators, which would allow for simultaneous minimization of the first- and second-order focusing effects.  
 
WEPC146 Plasma Lens of the ITEP Heavy Ion Accelerator plasma, ion, heavy-ion, simulation 2353
 
  • A. A. Drozdovsky, V. Abramenko, M. M. Basko, A. Golubev, D. D. Iosseliany, A. V. Kantsyrev, A. P. Kuznetsov, Yu. B. Novozhilov, O. V. Pronin, P. V. Sasorov, S. M. Savin, B. Y. Sharkov, V. V. Yanenko
    ITEP, Moscow
  At ITEP, on the bases of the TWAC-ITEP (Terawatt Accumulator) complex, a new facility is being built to conduct research at high energy densities in matter*. Application of a plasma lens to this area of research has a number of essential advantages in comparison with the traditional system based on quadruple lenses**. In accordance with the principal goals of this project, a pulse-power generator has been developed, with which a stable discharge current of up to 250 kA and duration of 4 μs has been achieved and which was used for experimental and theoretical investigation of the plasma lens performance. The plasma lens was installed into the exit channel of the TWAC accelerator complex, and its testing began by focusing of a C+6 beam with the ion energy of 200 MeV/a.u.m. As one of the first results, a minimum focal spot diameter of 350 μm FWHM has been measured at a target distance of 50 mm from the end of the discharge tube. The lens parameters were as follows: capacitance – 24 μF, charging voltage – 13 kV, discharge current – 220 kA, current half-wave – 4 μs, argon pressure – 3 mbar.

*Sharkov B. Yu. et al. Nucl. Instr. Meth. A464 (2001), p. 1.
** D. H.H. Hoffmann et al. Nucl. Instr. Methods Phys. Res., Sect. B 161-163, (2000), p. 9.

 
 
WEPC159 Compact Design of Race-track Microtron Magnets linac, microtron, induction, electron 2380
 
  • J. P. Rigla, Yu. A. Kubyshin
    UPC, Barcelona
  • S. Ferrer
    ALBA, Bellaterra
  • A. V. Poseryaev, V. I. Shvedunov
    MSU, Moscow
  A novel design of the end magnets for race-track microtrons (RTMs) is proposed. It consists of four-poles with the REPM material being used as a source of the magnetic field. For a proper choice of parameters of such magnetic system it can provide both the closure of the first orbit after beam reflection and required focusing properties. It is shown that such end magnet can be made quite compact thus allowing to build miniature RTMs. The procedure of design of the four-pole magnetic system and its optimization using the ANSYS code is described in detail.  
 
WEPC164 Development of Modulating Permanent Magnet Sextupole Lens for Focusing of Cold Neutrons sextupole, dipole, scattering, permanent-magnet 2392
 
  • M. Yamada, M. Ichikawa, Y. Iwashita, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • T. Ino, S. Muto, H. M. Shimizu
    KEK, Ibaraki
  A modulating permanent magnet sextupole lens that can focus pulsed cold neutrons is under development. It is based on the extended Halbach configuration to generate stronger magnetic field. In order to adjust the strength, the magnet is divided into two co-axial nested rings, where the inner ring is fixed and the outer ring can be rotated. Synchronizing the period of the modulation with that of pulsed neutron beam suppress the chromatic aberration. We have fabricated a half-scale model and studied the strength, the torque and the temperature rise caused by eddy current. Now we are developing the full-scale model improving such problems. These two scale models of magnet are described.  
 
WEPP008 Localizing Sources of Horizontal Orbit Oscillations at RHIC closed-orbit, luminosity, emittance, feedback 2539
 
  • R. Calaga, R. J. Michnoff, T. Satogata
    BNL, Upton, Long Island, New York
  Horizontal oscillations of the closed orbit at frequencies around 10Hz are observed at RHIC. These oscillations lead to beam beam offsets at the collision point, resulting in emittance growth and reduced luminosity. An approach to localize the sources of these vibrations using a special mode of RHIC turn-by-turn BPM data is presented. Data from the 2005-06 are analyzed to spatially resolve the location of the dominant sources.  
 
WEPP028 Flexible Momentum Compaction Return Arcs for RLAs linac, acceleration, lattice, quadrupole 2578
 
  • D. Trbojevic
    BNL, Upton, Long Island, New York
  • S. A. Bogacz
    Jefferson Lab, Newport News, Virginia
  • R. P. Johnson
    Muons, Inc, Batavia
  • M. Popovic
    Fermilab, Batavia, Illinois
  Neutrino Factories and Muon Colliders require rapid acceleration of short-lived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses a single Linac and teardrop return arcs can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity and the cost of the return arcs is appropriate. Flexible Momentum Compaction (FMC) lattice designs for the teardrop return arcs provide sufficient momentum acceptance to allow multiple passes of each sign of muon in one string of magnets to improve cost-effectiveness.  
 
WEPP047 Optics Implications of Implementing Nb3Sn Magnets in the LHC Phase I Upgrade optics, quadrupole, luminosity, lattice 2626
 
  • J. A. Johnstone, V. Kashikhin, N. V. Mokhov, A. V. Zlobin
    Fermilab, Batavia, Illinois
  CERN has encouraged the US-LARP collaboration to participate in Phase I of the LHC luminosity upgrade by analyzing the benefits gained by using Nb3Sn technology to replace the functionality of select magnets CERN is commited to construct using NbTi magnets. Early studies have shown that the much higher gradients (shorter magnetic lengths) and energy load of Nb3Sn magnets compared to their NbTi counterpars is very favorable – allowing the insertion of additional absorbers between Q1 & Q2, for example. This paper discusses the relative merits of the NbTi and Nb3Sn options.  
 
WEPP048 Recirculating Linear Muon Accelerator with Ramped Quadrupoles linac, optics, quadrupole, acceleration 2629
 
  • S. A. Bogacz
    Jefferson Lab, Newport News, Virginia
  • R. P. Johnson
    Muons, Inc, Batavia
  Neutrino Factories and Muon Colliders require rapid acceleration of short-lived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses a single Linac and teardrop return arcs can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity. A new concept of rapidly changing the strength of the RLA focusing quadrupoles as the muons gain energy is being developed to increase the number of passes that each muon will make in the RF cavities, leading to greater cost effectiveness. We are developing the optics and technical requirements for RLA designs, using RF cavities capable of simultaneous acceleration of both μ+ and μ- species, with pulsed Linac quadrupoles to allow the maximum number of passes.

Supported in part by DOE STTR grant DE-FG02-05ER86253

 
 
WEPP093 Prototype of Parallel Coupled Accelerating Structure coupling, resonance, controls, linac 2737
 
  • A. E. Levichev, V. M. Pavlov
    BINP SB RAS, Novosibirsk
  • Y. D. Chernousov
    ICKC, Novosibirsk
  • V. Ivannikov, I. V. Shebolaev
    ICKC SB RAS, Novosibirsk
  The prototype of parallel coupled accelerating structure is developed. It consists of five accelerating cavities, common excitation cavity and RF power waveguide feeder. The excitation cavity is a segment of rectangular waveguide loaded by cupper pins. The excitation cavity operate mode is TE105. Connection between excitation cavity and accelerating cavities is performed by magnetic field. The expressions for coupled factor excitation cavity to accelerating cavities and coefficient of efficiency for RF power transmission from generator to accelerating cavities are obtained using coupled cavities theory. The parallel coupled accelerating structure electrodynamic characteristics are measured.  
 
WEPP102 Design of the ILC RTML Extraction Lines extraction, kicker, collimation, damping 2752
 
  • S. Seletskiy, P. Tenenbaum, D. R. Walz
    SLAC, Menlo Park, California
  • N. Solyak
    Fermilab, Batavia, Illinois
  The Damping Ring to the Main Linac beamline (RTML) is equipped with three extraction lines (EL). Each EL can be used both for an emergency abort dumping of the beam and the tune-up continual train-by-train extraction. Two of the extraction lines are located downstream of the first and second stages of the RTML bunch compressor, and must accept both compressed and uncompressed beam with energy spread of 2.5 % and 0.15 % respectively. In this paper we report optical design that allowed us to minimize the length of the extraction lines while offsetting the beam dumps from the main line by the distance required for acceptable radiation level in the service tunnel. Proposed extraction lines can accommodate beams with different energy spreads at the same time providing the beam size suitable for the aluminum dump window.  
 
WEPP157 Lithium Lens for Positron Production System positron, target, optics, undulator 2856
 
  • A. A. Mikhailichenko
    Cornell University, Department of Physics, Ithaca, New York
  We represent optimized parameters for undulator-based positron production scheme for ILC-type machine. In particular we describe details of Lithium lens design suggested for usage in collection optics.  
 
THPC001 Synthesis of Optimal Nanoprobe (Linear Approximation) ion, target, controls, quadrupole 2969
 
  • S. N. Andrianov, A. A. Chernyshev, N. S. Edamenko, Yu. V. Tereshonkov
    St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
  High energy focused ion (proton) micro- and nanoprobes are intensively integrated to powerful analytical tool for different scientific and technological aims. Requirements for beam characteristics of similar focusing systems are extremely rigid. The value of demagnification for micro- and nanoprobes is the main optimality criteria, and as desirable value are in the range from 50 to 100 or even more. In the paper, we reconsider the basic properties of first order focusing systems from an optimal viewpoint. The matrix formalism allows us to formulate a nonlinear programming problem for all parameters of guiding elements. For this purpose there are used computer algebra methods and tools as the first step, and then some combination of special numerical methods. As a starting point for nanoprobe we consider so called “russian quadruplet”. On the next steps, we also investigate other types of nanoprobes. Some graphical and tabular data for nanoprobe parameters are cited as an example.  
 
THPC002 Synthesis of Optimal Nanoprobe (Nonlinear Approximation) octupole, quadrupole, controls, multipole 2972
 
  • S. N. Andrianov, N. S. Edamenko, Yu. V. Tereshonkov
    St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
  This paper is a continuation of the paper devoted to synthesis of optimal nanoprobe in linear approximation. Here the main goal is the optimization of nanoprobe including nonlinear aberrations of different nature up to third order. The matrix formalism for Lie algebraic methods is used to account for nonlinear aberrations. This method gives a possibility to consider nonlinear effects separately. Here we mean that a researcher can start or remove different kind of nonlinearities. This problem is separated into several parts. On the first step, we consider possibilities of additional optimization for some structures, selected on the step of linear approximation. The most of aberrations have harmful character, and their effect must be maximally decreased. Therefore, on the next steps, some we use analytical and numerical methods for generation of nonlinear corrected elements. The matrix formalism allows reducing the correction procedure to linear algebraic equations for aberration coefficients. Some examples of corresponding results are given.  
 
THPC003 Sum of Emittance in the Presence of a Linear Coupling emittance, coupling, betatron, quadrupole 2975
 
  • M. Aslaninejad, H. Ghasem
    IPM, Tehran
  In this article, the influence of linear coupling due to skew quadrupoles on the transverse equations of motion and emittances in accelerators is studied*. We first introduce the definition of the transverse single particle emittances using the Floquet transformation in alternating gradient as well as the constant focusing rings, then in the presence of the linear coupling, due to skew quadrupoles we introduce the coupled differential equations governing the particles motion and try to solve them by a direct method and also using the normal modes of motion to find the relation between the two transverse emittances. Based on smooth approximation and using the normal modes** we solve the equations of motion of a test charged particle and derive two new formulas for the sum of the emittances, and the conditions under which this sum is invariant.

*P. J.Bryant, CERN Acclerator School, CERN, PROCEEDINGS, 94-01, Vol. I.
**E. Metral, CERN/PS 2001-066(AE).

 
 
THPC040 Comparative Analysis of Different Kinds of Effects in the Nanoprobe controls, target, quadrupole, ion 3065
 
  • Yu. V. Tereshonkov, S. N. Andrianov
    St. Petersburg State University, Applied Mathematics & Control Processes Faculty, St. Petersburg
  Different kinds of parasitic effects in a nanoprobe are investigated. In this paper we consider the focusing system of nanoprobe, which consists of quadrupole lenses, but some results are also discussed for solenoids as focusing elements. The results of the similar analysis make it possible to design a number of goal-seeking strategies for selecting the optimal beam line structure. The influence of different linear and nonlinear aberrations is investigated using analytical and numerical methods and tools. For this purpose we present the beam line propagator based on a matrix formalism for Lie algebraic tools. In conclusion, some results of fulfilled modeling are analyzed.  
 
THPC077 Transportation Channel with Uniform Electron Distribution for the Kharkov Neutron Source based on Subcritical Assembly Driven with Linear Accelerator target, octupole, electron, quadrupole 3164
 
  • A. Y. Zelinsky, I. M. Karnaukhov
    NSC/KIPT, Kharkov
  Electron beam transportation channel from linear accelerator to the neutron target of NSC KIPT neutron source should provide uniform distribution of electrons on target surface to prevent overheating of the target and reduce thermal stress. In the presented channel the method of uniform beam distribution formation with linear focusing elements and nonlinear focusing elements (octupole magnets) we used. Linear focusing elements were used to provide particle transportation through the channel without losses and to form required beam sizes at the target. Nonlinear focusing elements were used to modulate transverse velocity of peripheral particles. As a result the uniform electron beam of rectangular shape can be formed at the target. In the report the main principles of transportation channel design and results of calculations for NSC KIPT neutron source based on subcritical assembly driven by electron accelerator are presented. Lattice and parameters of focusing elements are presented. Calculation results show that proposed transportation channel lattice can provide uniform beam of rectangular shape with sizes 66x66 mm.  
 
THPC083 Simulation Studies of Space-charge Effects in the LENS Nonlinear Transport Lines octupole, space-charge, simulation, target 3179
 
  • M. Hess, A. Bogdanov
    IUCF, Bloomington, Indiana
  The upgraded IUCF LENS beamline is designed to deliver a square shaped 13 MeV proton beam at 25 mA with a relatively uniform density using two octupole magnets for nonlinear focusing in both transverse directions. The space-charge effects in the LENS beamline (without nonlinear focusing) can vary the beam profile by roughly 8%-13% compared to a zero current beam. In this paper, we show the results of simulation studies of the LENS beamline which incorporate the effects of space-charge, as well as, nonlinear focusing from the octupole magnets. The simulations utilize self-consistent methods for computing the space-charge fields, since the beam density distribution can be nonlinear. We also show simulation results for beam currents in excess of 25 mA, which may be useful for future upgrades of LENS.  
 
THPC097 A Full Analytical Method to Determine Equilibrium Quantities of Mismatched Charged Particle Beams evolving in Linear Channels emittance, simulation, coupling, resonance 3203
 
  • R. P. Nunes, F. B. Rizzato
    IF-UFRGS, Porto Alegre
  The focus of this work is to show a full analytical expression to determine relevant equilibrium quantities of a magnetically focused and high-intensity charged particle beam when evolving in a linear channel. Through the current approach, some intermediate steps of our original hybrid model which have to be solved numerically now can be eliminated, leading to the obtainment of a full analytical expression. This expression relates initial beam parameters with those obtained at equilibrium, allowing that the fraction of halo particles f can be evaluated. As a consequence, through the developed model, beam quantities like the envelope and emittance can be naturally determined. This is important in the accelerator engineering, since halo characteristics is a factor to be considered in the design of its confinement structure. For validation, full self-consistent N-particle beam numerical simulations have been carried out and its results compared with the predictions supplied by the full analytical model. The agreement is shown to be nice as with the simulations as with the hybrid numerical-analytical version of the model.  
 
THPC098 Halo characterization of initially mismatched beams through phase-space modeling emittance, simulation, coupling, plasma 3206
 
  • R. P. Nunes, F. B. Rizzato
    IF-UFRGS, Porto Alegre
  This work discusses a method of characterizing the beam particles with just some assumptions about the entire beam phase-space topology. At equilibrium, the beam phase-space can be recognized as composed by almost two distinct regions: a thin horizontal branch over the r axis that is populated by the core particles and a curve branch in the dr/ds x r plane, which is populated by the halo particles. Since these regions have a regular shape, then it is readily possible to convert them to an analytical expression. Two distinct shapes have been employed (circular and elliptical) to model the beam halo branch. With this, all usual initial beam mismatch values are covered with accuracy to determine the beam envelope and emittance at equilibrium. Full self-consistent N-particle beam simulations have been carried out and its results compared with the ones obtained with the model. Results agreed nice for all analyzed mismatch cases.  
 
THPC100 Collisionless Relaxation in the Transport of Space Charge Dominated Beams simulation, space-charge, resonance, plasma 3209
 
  • R. Pakter, Y. Levin, T. N. Teles
    IF-UFRGS, Porto Alegre
  Relaxation to a final stationary state of particles interacting through long-range forces, such as Coulomb, is intrinsically different than that of systems with short-range interactions. While in the latter case it is known that the interparticle collisions drive the system to an equilibrium Maxwell-Boltzmann distribution, in the former case, the collision duration time diverges and the state of thermodynamic equilibrium is never reached. In this paper, a theory is presented which allows to quantitatively predict the final stationary state achieved by a transported space-charge dominated beam during a process of collisionless relaxation*. It is shown that a fully matched beam relaxes to a Fermi-Dirac distribution. However, when a mismatch is present and the beam oscillates, halo formation leads to a phase separation. The theory developed allows to quantitatively predict both the density and the velocity distributions in the final stationary state, including the halo.

* Y. Levin, R. Pakter, and T. N. Teles, Phys. Rev. Lett., 100, 040604 (2008).

 
 
THPC103 Wave Breaking and Test Particle Dynamics in Inhomogeneous Beams emittance, simulation, plasma, space-charge 3218
 
  • F. B. Rizzato, Y. Levin, R. P. Nunes, R. Pakter, E. G. Souza
    IF-UFRGS, Porto Alegre
  This work analyzes the dynamics of inhomogeneous, magnetically focused high-intensity beams of charged particles. While for homogeneous beams the whole system oscillates with a single frequency, any inhomogeneity leads to propagating transverse density waves which eventually result in a singular density build up, causing wave breaking and jet formation. Wave breaking is shown to relax the mismatched beam and we make use of Lynden-Bell's theory of violent relaxation to estimate characteristics of the relaxed state.  
 
THPC105 Self-consistent Transverse Dynamics and Interbunch Energy Exchange in Dielectric Loaded Wakefield Accelerating Structures electron, acceleration, transverse-dynamics, vacuum 3224
 
  • I. L. Sheynman
    LETI, Saint-Petersburg
  • A. Kanareykin
    Euclid TechLabs, LLC, Solon, Ohio
  The self-consistent transverse dynamics of high current relativistic electron beams used for generating wakefields in dielectric loaded structures is investigated. The primary application of this work is to multi-bunch wakefield acceleration. The maximum distance the high current beam can travel through the structure in the absence of focusing without experiencing beam breakup and the energy transferred to the accelerated electron bunch will be presented. We consider both ramped and uniform charge distributions in the sequence of high current drive bunches. The ramped drive charge distribution is compared to the case of a uniform charge distribution in terms of the requirements for the beam focusing system and the effectiveness of the energy transfer to the accelerated electron bunch.  
 
THPC112 KONUS Dynamics and H-mode DTL Structures for EUROTRANS and IFMIF beam-losses, simulation, rfq, linac 3239
 
  • C. Zhang, M. Busch, H. Klein, H. Podlech, U. Ratzinger, R. Tiede
    IAP, Frankfurt am Main
  During the last two decades, the combination of the KONUS beam dynamics and H-mode DTL structures has been developed as an efficient solution for accelerating low- and medium-energy proton and ion beams. EUROTRANS is a EUROpean Research Programme for the TRANSmutation of High Level Nuclear Waste in an Accelerator Driven System. IFMIF is a planned International Fusion Material Irradiation Facility to test materials for fusion reactors. For the driver linacs of both projects, two H-DTLs have been proposed to cover the energy ranges of 3–17MeV and 5–40MeV, respectively. The beam dynamics designs as well as the error studies of the H-DTLs are presented in this paper.  
 
THPP008 Hamiltonian Approach to the Dynamics of Particles in Non-scaling FFAG Accelerators acceleration, lattice, betatron, proton 3392
 
  • B. D. Muratori, S. L. Smith, S. I. Tzenov
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Starting from first principle the Hamiltonian formalism for the description of the dynamics of particles in non-scaling FFAG machines has been developed. The stationary reference (closed) orbit has been found within the Hamiltonian framework. The dependence of the path length on the energy deviation has been described in terms of higher order dispersion functions. The latter have been used subsequently to specify the longitudinal part of the Hamiltonian. It has been shown that higher order phase slip coefficients should be taken into account to adequately describe the acceleration in non-scaling FFAG accelerators.  
 
THPP009 Injection and Extraction Orbits and Twiss Parameters for the EMMA Ring injection, extraction, kicker, betatron 3395
 
  • B. D. Muratori, S. L. Smith, S. I. Tzenov
    STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Using the FFEMMAG code, the injection and extraction orbits for the EMMA ring at a variety of injection and extraction energies together with the Twiss parameters to be used for matching have been calculated. The orbits include two kickers together with a septum at both injection and extraction. The FFEMMAG code has been used in conjunction with several scripts so as to be able to scan the parameter space of the two kicker strengths for a section of the EMMA ring. The results confirm the choice of magnet and vacuum pipe apertures as being adequate to operate EMMA from 10 to 20 MeV.  
 
THPP019 Adjustment of a New Pre-stripping Section the Multicharge Ion Linear Accelerator (MILAC) ion, simulation, vacuum, acceleration 3410
 
  • O. F. Dyachenko, V. A. Bomko, Ye. V. Ivakhno, A. P. Kobets, V. I. Misjura, V. V. Mytrochenko, A. V. Zabotin, B. V. Zajtsev
    NSC/KIPT, Kharkov
  In the Kharkov Institute of Physics and Technology the works on commissioning of a new prestripping section (A/q = 4), intend for accelerating a high current beam of light ions from 30 keV/u to 975 keV/u come to the end. Results of final tuning of irregular interdigital accelerating structure with alternating phase focusing and stepped changing the synchronous phase along the focusing period are presented. Process of preliminary adjustment of structure by means of traditional developed earlier methods: the additional current-carrying stems and the end resonant tuning elements (ERTEs) is described. New effective inductance-capacitor tuning devices as rods located on the drift tube side, opposite to their holders («contrivance») are developed and their use in real structure is shown. «Contrivances» have proved as the effective element of tuning locally influencing value of an electric field in the nearest gaps and lowering resonant frequency without noticeable worsening of electrodynamic characteristics of resonant system.  
 
THPP026 IH Accelerating Structures with PMQ Focusing for Low-energy Light Ions simulation, quadrupole, impedance, ion 3428
 
  • S. S. Kurennoy, S. Konecni, J. F. O'Hara, L. Rybarcyk
    LANL, Los Alamos, New Mexico
  We are developing high-efficiency room-temperature RF accelerating structures for beam velocities in the range of a few percent of the speed of light by merging two well-known ideas: inter-digital H-mode (IH) cavities and the transverse beam focusing with permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we have proved that such structures provide a very efficient and practical accelerator for light-ion beams of considerable currents. The IH accelerating structures with PMQ focusing following a short RFQ can be used in the front end of ion linacs or in stand-alone applications such as a compact deuteron-beam accelerator up to the energy of a few MeV.  
 
THPP044 Experience with the SNS SC Linac linac, beam-losses, emittance, beam-transport 3461
 
  • Y. Zhang, A. V. Aleksandrov, C. K. Allen, I. E. Campisi, S. M. Cousineau, V. V. Danilov, J. Galambos, J. A. Holmes, D.-O. Jeon, S.-H. Kim, T. A. Pelaia, A. P. Shishlo
    ORNL, Oak Ridge, Tennessee
  The SNS SC linac (SCL) is designed to deliver 1 GeV, up to 1.56 MW pulsed H- beams for neutron production. Beam commissioning of the SNS accelerator systems completed in June 2006 with the maximum linac output beam energy approximately 952 MeV. In 2007, we successfully tuned the SCL for 1 GeV beams during a test run, and the SNS linac achieved its design energy for the first time. During the linac tune-up, phase scan signature matching, drifting beam measurement as well as linac RF cavity phase scaling was applied. In this paper, we will introduce the experiences with the SCL, and we will also briefly discuss beam parameter measurements.


 
 
THPP065 3D Simulation of the Axial Injection Beam Line of DC350 Cyclotron cyclotron, simulation, ion, injection 3509
 
  • N. Yu. Kazarinov, V. Aleksandrov, V. Shevtsov, A. Tuzikov
    JINR, Dubna, Moscow Region
  DC-350 is the novel cyclotron designed in Flerov Laboratory of Nuclear Reaction of Joint Institute for Nuclear Research. It is intended for the nuclear and applied physics experiments. The axial injection channel of the DC-350 cyclotron gives possibility for transportation of the high intensity ion beam from Li to Bi obtained in the superconducting ECR-ion source (SECR). The beam focusing in the beam line after the analyzing bending magnet is provided by solenoidal lenses. The linear and sinusoidal bunchers installed in the vertical part of the channel are used for increasing of the accelerating efficiency. The 3D simulation results of the focusing and bunching systems of the axial injection beam line are presented.  
 
THPP074 Optimal Design of a High Current MEBT with Chopper kicker, emittance, target, beam-transport 3533
 
  • A. V. Aleksandrov
    ORNL, Oak Ridge, Tennessee
  Many existing and proposed projects require a certain temporal structure imposed on the beam pulse, e.g., creating gaps for low-loss extraction from a circular accelerator. Usually it is achieved using chopper systems. In order to reduce average beam power on the target and simplify kicker requirements chopper system is located in a lower energy part of the accelerator, typically in the medium energy transport line (MEBT) between the RFQ and the linac. Many of the MEBT layouts, proposed and in use, look very much alike and try to achieve a compromise between two opposing requirements of providing strong transverse focusing and sufficiently long empty drifts for the kickers. As a result, both requirements are not fully satisfied leading to space charge induced emittance increase and very challenging technical specifications for the kicker and its power supply. These difficulties quickly increase with the beam current. We propose a different MEBT layout, which does not compromise quality of beam transport and allows space for a kicker with any reasonable parameters. A generic design of a 5.5m long MEBT transporting 100mA with emittance increase of less than 5% is shown as an example.  
 
THPP075 Beam Dynamics of the IFMIF-EVEDA RFQ rfq, emittance, multipole, beam-losses 3536
 
  • M. Comunian, A. Pisent, P. A. Posocco
    INFN/LNL, Legnaro, Padova
  • E. Fagotti
    Consorzio RFX, Euratom ENEA Association, Padova
  The IFMIF project is aimed at the realization of an intense neutron beam facility for testing the irradiation of the materials to be used for fusion reactors. EVEDA (Engineering Validation Engineering Design Activities) is a first step towards the implementation of this challenging project and consists of the construction of prototypes of the main units. In particular INFN-LNL is in charge of the construction of a 5 MeV, 125 mA, deuteron RFQ at 175 MHz. In this article the main aspects of the beam dynamics design of this RFQ are described, namely the optimization of the length and the transmission issues, the main outcomes and comparison of the PARMTEQM and TOUTATIS codes used for the simulations and the basic aspects of the errors studies.  
 
THPP080 A Superconducting CH-Linac for IFMIF linac, rfq, acceleration, beam-losses 3548
 
  • H. Podlech, A. Bechtold, M. Busch, F. Dziuba, H. Klein, H. Liebermann, U. Ratzinger, R. Tiede, C. Zhang
    IAP, Frankfurt am Main
  The IFMIF accelerator which has to provide a 40 MeV 250 mA Deuteron beam requires a duty cycle of 100%. The IAP Frankfurt has proposed 175 MHz H-type drift tube linac consisting of an IH-cavity and a chain of superconducting CH-cavities. A superconducting CH-prototype cavity has been tested very successfully and reached effective gradients of 7 MV/m. Two rf power couplers are necessary to feed one CH-cavity. The maximum rf power per cavity is approximately 500 kW. As amplifiers the originally foreseen 1 MW tubes or 300 kW tubes can be used. The focusing scheme in the CH-linac is based on superconducting solenoids. Beam dynamics simulations have been performed with an error analysis using the LORASR code based on the KONUS dynamics. An updated and improved linac design will be presented. A contribution of IAP for the EVEDA phase could consists of the construction and the test of the room temperature IH-cavity and the first complete CH cryo-module. A study together with industry has been already performed regarding the production process and the system integration of auxiliary equipment like couplers and tuner.  
 
THPP106 Neutrino Beam Line at J-PARC target, proton, beam-losses, controls 3614
 
  • M. Shibata
    KEK, Tsukuba
  A neutrino beam line for the long baseline neutrino oscillation experiment T2K is under construction at J-PARC in Tokai. Construction is proceeding on schedule and commissioning of the beam line will start in April of 2009. Proton beams are injected from the main ring, then bent about 80 degrees using superconducting magnets directing the beam toward the Super-Kamiokande detector. Muon neutrinos are produced from pions produced at the target. Precise beam tuning is quite important in our beam line since the beam intensity is expected to be 750 kW and failure of the tuning system may cause damage to the beam line components. For this purpose, we install four types of beam monitors in the primary beam line:
  1. CT for beam intensity,
  2. ESM for beam position,
  3. SSEM for beam profile and
  4. a loss monitor.
Specifications and current status of these monitors will be reported. We report also on ground motion in the facility. Since the floor level of the neutrino beam line was observed to sink after initial construction, a level meter was installed to observe the motion continuously as it could be a serious problem for beam line alignment.