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MOYCH01 The TESLA XFEL Project hadron, collider, vacuum, cryogenics 11
 
  • H. Weise
    DESY, Hamburg
  The overall layout of the X-Ray FEL to be built in international collaboration at DESY will be described. This includes the envisaged operation parameters for the linear accelerator which will use TESLA technology. Main emphasis is put on the specification of the superconducting accelerator modules. Other linac components will be described as well. Work packages needed to finalize the linac design will be presented. A summary of the status of the preparation work will be given.  
Video of talk
Transparencies
 
MOOCH02 First Full Beam Loading Operation with the CTF3 Linac simulation, acceleration, alignment, emittance 39
 
  • R. Corsini, H.-H. Braun, G. Carron, O. Forstner, G. Geschonke, E. Jensen, L. Rinolfi, D. Schulte, F. Tecker, L. Thorndahl
    CERN, Geneva
  • M. Bernard, G. Bienvenu, T. Garvey, R. Roux
    LAL, Orsay
  • A. Ferrari
    Uppsala University, Uppsala
  • L. Groening
    GSI, Darmstadt
  • R.F. Koontz, R.H. Miller, R.D. Ruth, A.D. Yeremian
    SLAC, Menlo Park, California
  • T. Lefevre
    NU, Evanston
  The aim of the CLIC Study is to investigate the feasibility of a high luminosity, multi-TeV linear e+e- collider. CLIC is based on a two-beam method, in which a high current drive beam is decelerated to produce 30 GHz RF power needed for high-gradient acceleration of the main beam running parallel to it. To demonstrate the outstanding feasibility issues of the scheme a new CLIC Test Facility, CTF3, is being constructed at CERN by an international collaboration. In its final configuration CTF3 will consist of a 150 MeV drive beam linac followed by a 42 m long delay loop and an 84 m combiner ring. The installation will include a 30 GHz high power test stand, a representative CLIC module and a test decelerator. The first part of the linac was installed and commissioned with beam in 2003. The first issue addressed was the generation and acceleration of a high-current drive beam in the "full beam loading" condition where RF power is converted into beam power with an efficiency of more than 90%. The full beam loading operation was successfully demonstrated with the nominal beam current of 3.5 A. A variety of beam measurements have been performed, showing good agreement with expectations.  
Video of talk
Transparencies
 
MOPKF006 Enhancements of Top-up Operation at the Swiss Light Source emittance, electron, undulator, alignment 309
 
  • B. Kalantari, T. Korhonen, A. Lüdeke, C. Quitmann
    PSI, Villigen
  Since the first experience on 2001, Top-Up is the standard mode of operation at the Swiss Light Source (SLS) for users. In order to fulfill the ongoing demands of machine experts and experiments we have had to add more functionality to the Top-Up mode thus make it more flexible. Some time-resolved experiments require a constant charge in a single isolated bucket in the gap of the normal filling of a bunch train of 80% of the circumference of the storage ring. Therefore the Hybrid application was developed that keeps the beam current distribution constant in this mode. We developed a maintenance mode too, to allow to work continuously on the Linac and booster - for example to optimize injection/extraction - without disturbing the Top-up for user operation. Even beam destructive experiments at the Linac during Top-Up or Hybrid operation are supported, where the Linac can be used synchronously at the times between successive refilling of the storage ring. The flexible control and timing systems at the SLS made these applications feasible. We describe the controls, operation and applications of each of the above functionalities in this paper.  
 
MOPKF009 Photoinjector Studies for the BESSY Soft X-ray FEL gun, electron, undulator, alignment 315
 
  • F. Marhauser
    BESSY GmbH, Berlin
  A linac driven soft X-Ray FEL facility has been proposed at BESSY with the aim to produce high brilliance photon beams within the energy range of 20eV to 1keV. The driver linac is based on superconducting (sc) L-Band rf-technolgy to enable cw operation of the FEL. As the electron beam emittance directly influence the photon beam characteristics, transverse slice emittances of 1.5pimmmrad are envisaged as a target goal. This demands for a high brilliance laser driven photoinjector rf-gun as electron source. For the first years of operation it is intended to use well known normal conducting (nc) L-Band rf-gun technology thereby restricting the macropulse repetition rate to 1 kHz to cope with the thermal power dissipation. At a later stage the nc rf-gun shall be replaced by a sc rf-gun, which is favoured conceptually as it allows to generate outmost flexible bunch patterns according to the needs of the experiments by fully exploiting the capabilities of the sc linac. This paper details the design considerations for a high power nc rf-gun complemented by results of beam dynamic studies up to the exit of the booster linac using ASTRA. Perspectives for the use of a sc photoinjector gun cavity are addressed.  
 
MOPKF018 Injector and Bunch Compressor for the European XFEL Project wiggler, damping, gun, alignment 342
 
  • Y. Kim, Y. Kim, D. Son
    CHEP, Daegu
  • M. Dohlus, K. Floettmann, T. Limberg
    DESY, Hamburg
  For the proper operation of European XFEL project, we should supply high quality electron beams with low emittance, short bunch length, and low energy spread to a 200 m long undulator. In this paper, we describe the optimization and design concepts of the XFEL injector and bunch compressors to control the beam parameter dilution due to the microbunching instability and CSR.  
 
MOPKF027 Optimizing the PITZ Electron Source for the VUV-FEL electron, wiggler, damping, alignment 360
 
  • M. Krasilnikov, J. Bähr, U. Gensch, H.-J. Grabosch, J.H. Han, D. Lipka, V. Miltchev, A. Oppelt, B. Petrosyan, D. Pose, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • K. Abrahamyan
    YerPhI, Yerevan
  • W. Ackermann, R. Cee, W.F.O. Müller, S. Setzer, T. Weiland
    TEMF, Darmstadt
  • G. Asova, G. Dimitrov, I. Tsakov
    INRNE, Sofia
  • I. Bohnet, J.-P. Carneiro, K. Floettmann, S. Riemann, S. Schreiber
    DESY, Hamburg
  • M.V. Hartrott, E. Jaeschke, D. Krämer, R. Richter
    BESSY GmbH, Berlin
  • P. Michelato, L. Monaco, C. Pagani, D. Sertore
    INFN/LASA, Segrate (MI)
  • J. Rossbach
    Uni HH, Hamburg
  • W. Sandner, I. Will
    MBI, Berlin
  The goal of the Photo Injector Test Facility at DESY Zeuthen (PITZ) is to test and optimize electron sources for Free Electron Lasers and future linear colliders. At the end of 2003 the first stage of PITZ (PITZ1) has been successfully completed, resulting in the installation of the PITZ RF gun at the Vacuum Ultra Violet - Free Electron Laser (VUV-FEL) at DESY Hamburg. The main results achieved during the PITZ1 extensive measurement program are discussed in this paper. A minimum normalized beam emittance of about 1.5 pi mm mrad for 1 nC electron bunch charge has been reached by optimizing numerous photo injector parameters, e.g. longitudinal and transverse profiles of the photocathode laser, RF phase, main and bucking solenoid current. The second stage of PITZ (PITZ2), being a large extension of the facility and its research program, has started now. Recent progress on the PITZ2 developments will be reported as well.  
 
MOPKF029 Seeding High Gain Harmonic Generation with Laser Harmonics produced in Gases wiggler, damping, alignment, laser 363
 
  • G. Lambert, B. Carré, M.-E. Couprie, D. Garzella
    CEA/Saclay, Gif-sur-Yvette
  • A. Doria, L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma)
  • T. Hara, H. Kitamura, T. Shintake
    RIKEN Spring-8 Harima, Hyogo
  Free electron lasers employing High Gain Harmonic Generation (HGHG) schemes are very promising coherent light sources for the soft X-ray regime. They offer both transverse and longitudinal coherence, inversely to Self Amplified Spontaneous Emission schemes, where the longitudinal coherence is limited. We propose here to seed HGHG with high harmonics produced by a Ti:Sa femtosecond laser focused on a gas jet, tuneable in the 100-10 nm spectral region. Specifities concerning the implementation of this particular laser source as a seed for HGHG are investigated. Theoretical ad numerical calculations (using PERSEO in particular) are given, for the cases of the SCSS and ARC-EN-CIEL projects.  
 
MOPKF037 FERMI@ELETTRA: 100 nm - 10 nm Single Pass FEL User Facility injection, booster, wiggler, vacuum 387
 
  • R.J. Bakker, C. Bocchetta, P. Craievich, G. D'Auria, M. Danailov, G. De Ninno, S. Di Mitri, B. Diviacco, G. Pangon, L. Rumiz, L. Tosi, V. Verzilov, D. Zangrando
    ELETTRA, Basovizza, Trieste
  The FERMI@ELETTRA project is an initiative from ELETTRA, INFM and other Italian institutes, to construct a single-pass FEL user-facility for the wavelength range from 100 nm (12 eV) to 10 nm (124 eV), to be located next to the third-generation synchrotron radiation facility ELETTRA in Trieste, Italy. The project is concentrated around the existing 1.2-GeV S-band linac, i.e., the injector for the storage ring. Presently the linac is only operational for approximately 2 hours per day. The remaining time is available for the construction and operation of an FEL but modifications and operation must be planned such that operation of the storage ring can be guaranteed until the completion of a new full-energy injector (spring 2006). At this moment the FEL project evolves from a conceptional design stage towards a technical design and the actual implementation. Key issues are: incorporation of the free-electron laser in the infrastructure of the Sincrotrone Trieste, adjustments of the linac to facilitate FEL operation, required additional civil engineering, undulator design, FEL seeding options, and beamline design. This paper serves as an overview of the project in combination with a discussion of the critical issues involved.  
 
MOPKF039 The ELETTRA Superconducting Wiggler injection, booster, vacuum, damping 390
 
  • L. Tosi, C. Knapic, D. Zangrando
    ELETTRA, Basovizza, Trieste
  A 3.5 Tesla 64 mm period superconducting wiggler has been installed in the ELETTRA storage ring as a photon source for a future X-ray diffraction beamline. After several technological upgrades, a series of measurements were carried out to characterize the device and its effects on the electron beam, such as optics distortion and dynamic aperture. A description of the upgrades and measurements are presented.  
 
MOPKF040 Effect of Electron-beam Feedbacks on the ELETTRA Storage-ring Free-electron Laser injection, electron, laser, booster 393
 
  • M. Trovò, D. Bulfone, M. Danailov, G. De Ninno, B. Diviacco, V. Forchi', M. Lonza
    ELETTRA, Basovizza, Trieste
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma)
  As is well known, the stability of a storage-ring free-electron laser is strongly related to that of the electron beam. With respect to second-generation devices, such as Super ACO and UVSOR, the free-electron laser at ELETTRA is characterized by a noticeably higher gain and, consequently, shows to be much more sensitive to electron-beam instabilities. In order to counteract the impact of such instabilities, both a longitudinal multibunch and a local orbit feedbacks have been implemented for free-electron laser operation. Aim of this paper is to report on the beneficial effect of these feedback systems on the laser performance.  
 
MOPKF042 Status of the SPARC Project injection, electron, booster, vacuum 399
 
  • M. Ferrario, D. Alesini, M. Bellaveglia, S. Bertolucci, M.E. Biagini, R. Boni, M. Boscolo, M. Castellano, A. Clozza, G. Di Pirro, A. Drago, A. Esposito, D. Filippetto, V. Fusco, A. Gallo, A. Ghigo, S. Guiducci, M. Incurvati, C. Ligi, F. Marcellini, L. Pellegrino, M.A. Preger, R. Ricci, C. Sanelli, M. Serio, F. Sgamma, B. Spataro, A. Stecchi, A. Stella, F. Tazzioli, C. Vaccarezza, M. Vescovi, C. Vicario
    INFN/LNF, Frascati (Roma)
  • F. Alessandria, A. Bacci, M. Mauri
    INFN/LASA, Segrate (MI)
  • I. Boscolo, F. Brogli, S. Cialdi, C. De Martinis, D. Giove, C. Maroli, V. Petrillo, M. Romé, L. Serafini
    INFN-Milano, Milano
  • L. Catani, E.C. Chiadroni, A. Cianchi, S. Tazzari
    Università di Roma II Tor Vergata, Roma
  • F. Ciocci, G. Dattoli, A. Doria, F. Flora, G.P. Gallerano, L. Giannessi, E. Giovenale, G. Messina, L. Mezi, P.L. Ottaviani, L. Picardi, M. Quattromini, A. Renieri, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • D. Dowell, P. Emma, C. Limborg-Deprey, D. Palmer
    SLAC, Menlo Park, California
  • D. Levi, M. Mattioli, G. Medici
    Università di Roma I La Sapienza, Roma
  • M.  Migliorati, A. Mostacci, L. Palumbo
    Rome University La Sapienza, Roma
  • P. Musumeci, J. Rosenzweig
    UCLA, Los Angeles, California
  • M. Nisoli, S. Stagira, S. de Silvestri
    Politecnico/Milano, Milano
  The aim of the SPARC project is to promote an R&D activity oriented to the development of a high brightness photoinjector to drive SASE-FEL experiments at 500 nm and higher harmonics generation. It has been proposed by a collaboration among ENEA-INFN-CNR-Universita‘ di Roma Tor Vergata-INFM-ST and funded by the Italian Government with a 3 year time schedule. The machine will be installed at LNF, inside an existing underground bunker. It is comprised of an rf gun driven by a Ti:Sa laser to produce 10-ps flat top pulses on the photocathode, injecting into three SLAC accelerating sections. We foresee conducting investigations on the emittance correction and on the rf compression techniques up to kA level. The SPARC photoinjector can be used also to investigate beam physics issues like surface-roughness-induced wake fields, bunch-length measurements in the sub-ps range, emittance degradation in magnetic compressors due to CSR. We present in this paper the status of the design activities of the injector and of the undulator. The first test on diagnostic prototypes and the first experimental achievements of the flat top laser pulse production are also discussed.  
 
MOPKF049 Design Study for a 205 MeV Energy Recovery Linac Test Facility at the KEK injection, booster, cathode, insertion 420
 
  • E.-S. Kim
    PAL, Pohang
  • K. Yokoya
    KEK, Ibaraki
  We present a lattice and beam dynmics analysis for a 200 MeV energy recovery linac test facility at the KEK. The test facility consists of a photocathode rf gun, a 5 MeV injector, a merger, 200 MeV superconducting linac, TBA sections and beam dump line. Beam parameters and optimal optics to relaize the energy recovery linac are described. Simulation results on emittance growth due to HOMs in the superconducting linac and coherent synchrotron radiation in the designed lattice are presented.  
 
MOPKF050 Current Heart-like Wiggler wiggler, injection, booster, cathode 423
 
  • V.I.R. Niculescu, G.R. Anda, F. Scarlat
    INFLPR, Bucharest - Magurele
  • V. Babin
    INOE, Bucharest
  • C. Stancu, A. Tudorache
    Bucharest University, Faculty of Physics, Bucharest-Magurele
  A new wiggler structure for free electron lasers is presented. Current hart-like wiggler produced magnetic fields which were spatially periodic. The current wiggler structure was in the shape of stacks of modified circle wires. The current had alternating directions. The magnetic field components for each wire present a C2 symmetry (for a model with 3 branches). The wiggler transverse cross - section in arbitrary units was given by the following expressions: x = R(d+sin(3j))cos(j) , y = R(d+sin(3j))sin(j) , z = constant, where d and R are the parameters. In cylindrical coordinates the Biot - Savart law was evaluated numerically. The magnetic field aspect was mainly transversal and also easily adjusted with the current . The versatility of this structure permits new geometrical forms and developments in the wiggler and wiggler design .  
 
MOPKF052 Design of an In Archromatic Superconducting Wiggler at NSRRC injection, wiggler, booster, cathode 425
 
  • C.-H. Chang, H.-H. Chen, T.-C. Fan, G.-Y. Hsiung, M.-H. Huang, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  A 15-pole superconducting wiggler with period length of 6 cm is designed for National Synchrotron Research Center (NSRRC) in Taiwan. The compact superconducting wiggler will be installed near the second bending magnet of the triple bend achromat section in the 1.5 GeV storage ring. This wiggler magnet with maximum peak field of 3.2 T at pole gap width of 19 mm is operated in 4.2 K liquid helium vessel. A 5-pole prototype magnet is tested and measured to verify the magnetic field performance in the testing dewar. Furthermore, the cryogenic considerations and thermal analysis in the 4.2 K wiggler magnet and the 77 K vacuum chamber are also presented in this work.  
 
MOPKF053 Pulsed-wire Method of Field Measurement on Short Elliptically Polarized Undulator injection, wiggler, booster, cathode 428
 
  • T.-C. Fan, C.-S. Hwang, F.-Y. Lin
    NSRRC, Hsinchu
  With two sets of photo illuminator and detector, scientists already have applied pulsed-wire method to measure the magnetic field along two mutually perpendicular directions. Two-dimensional pulsed-wire method is useful for the test of elliptically polarlized undulator (EPU). We tried to use this method to observe the first integral and second integral fields of a short EPU in real time during the polarization tuning. We have taken care more details than the pulsed-wire measurement of planner undulators. The phase difference, the relative field strength along two direction as well as the precise centerline can be achieved.  
 
MOPKF077 Reducing the Synchrotron Radiation on RF Cavity Surfaces in an Energy-recovery Linac electron, wiggler, radiation, cathode 494
 
  • G. Hoffstaetter, M. Liepe, T. Tanabe
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  In Energy Recovery Linac (ERL) light sources, a high energy, high current beam has to be bend into a superconducting linac to be decelerated. The synchrotron radiation produced in the last bending magnet before the linac shines into the superconducting structures if not collimated appropriately. Due to the length of the linac, the radiation cannot be completely guided through the superconducting structure, as in existing SRF storage rings. For the example of an ERL extension to the existing CESR storage ring at Cornell we estimate the magnitude of this problem by quantifying the heat load that can be accepted on a superconducting surface and by analyzing how much radiation is deposited on the cavity surfaces for different collimation schemes.  
 
MOPKF078 ERL Upgrade of an Existing X-ray Facility: CHESS at CESR electron, wiggler, cathode, laser 497
 
  • G. Hoffstaetter, M. Liepe, R.M. Talman, M. Tigner
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • I. Bazarov, H. Bilderback, M. Billing, S. Gruner, D. Sagan, C.K. Sinclair
    Cornell University, Department of Physics, Ithaca, New York
  CORNELL has proposed an Energy-Recovery Linac (ERL) based synchrotron-light facility which can provide improved x-ray radiation due to the high beam quality that can be available from a linac. To additionally utilize beam currents that are competitive with ring-based light sources, the linac has to operate with the novel technique of energy recovery, the feasibility of which CORNELL plans to demonstrate in a downscaled prototype ERL. Here we present an ERL upgrade of the existing 2nd generation light source CHESS at CESR. This proposed upgrade suggests how existing storage rings can be extended to ERL light sources with much improved beam qualities.  
 
MOPKF079 The Linac Coherent Light Source Photo-Injector Overview and Some Design Details wiggler, cathode, gun, insertion 500
 
  • D. Dowell, R. Akre, L.D. Bentson, P. Bolton, R.F. Boyce, R. Carr, J.E. Clendenin, S.M. Gierman, A. Gilevich, K. Kotturi, Z. Li, C. Limborg-Deprey, W. Linebarger, M. Ortega, J. Schmerge, P. Smith, L. Xiao
    SLAC, Menlo Park, California
  The Linac Coherent Light Source (LCLS)[*] is a SASE free electron laser using the last 1/3 of the SLAC two mile linac to produce 1.5 to 15 angstrom x-rays in a 100 meter long undulator. A new 135 MeV photo-injector will be built in an existing, off-axis vault at the 2/3 point of the main linac. The injector accelerator consists of a BNL/SLAC/UCLA s-band gun followed by two 3-meter long SLAC accelerator sections. The 5.6 MeV beam from the gun is matched into the first accelerator section and accelerated to 135 MeV before injection onto the main linac axis with a 35 degree bend [**]. Several modifications have been made to the rf gun, linac and beamline as well as the inclusion of several diagnostics have been incorporated into the injector design to achieve the required 1.2 micron projected emittance at a charge of 1 nC. In addition, a laser heater [***], will increase the uncorrelated energy spread to suppress coherent synchrotron radiation and longitudinal space charge instabilities in the main accelerator and bunch compressors [****]. The configuration and function of the major injector components will be described.

* Linac Coherent Light Source (LCLS) CDR No. SLAC-R-593 UC-414, 2002 ** C. Limborg et al., Proc. of the 2003 International FEL Conf *** R. Carr et al, Contrib. to these proceedings **** Z. Huang et al., Contrib. to these proceedings

 
 
MOPKF080 Controlling Emittance Growth in an FEL Beam Conditioner wiggler, cathode, gun, electron 503
 
  • P. Emma, G.V. Stupakov
    SLAC, Menlo Park, California
  It has been proposed [*] to 'condition' an electron beam prior to the undulator of a Free-Electron Laser (FEL) by increasing each particle's energy in proportion to the square of its transverse betatron amplitude. This conditioning enhances FEL gain by reducing the axial velocity spread within the electron bunch. Previosly [**] we presented a system that allows conditioning of the beam on a relatively short distance, however, it suffers from projected beam emittance growth to the extent that makes it impractical for application for X-ray FELs. In this paper we extend analysis proposed by A. Wolski for general requirements to the conditioner which does not have such emittance growth. We also present a possible implementation of a beam conditioner consisting of multiple solenoid cells in combination with quadrupole magnets. Simulations show that in such a system the emittance growth can be suppressed to acceptable level, albeit in a longer system.

* A. Sessler et al., Phys. Rev. Lett., 68, 309 (1992).** P. Emma and G. Stupakov. PRSTAB, 6, 030701 (2003).

 
 
MOPKF081 Peak Current Optimization for LCLS Bunch Compressor 2 wiggler, cathode, gun, electron 506
 
  • A.C. Kabel, P. Emma
    SLAC, Menlo Park, California
  The performance of an FEL will be a function of both the driving bunch's current and its slice emittance. We have studied a set of parameters for the bunch compression section of the LCLS, simulating the effects of Coherent Synchrotron Radiation (CSR) on the slice emittance of the bunch core as a function of peak current. We use the code TraFiC4 for a three-dimensional, self-consistent simulation on parallel computers. While higher currents will increase FEL performance, its detrimental effects, due to CSR, on slice emittance will counteract this beneficial effect. From our simulations, we determine a near-optimum current, balancing these effects.  
 
MOPKF082 A Multi-bunch, Three-dimensional, Strong-strong Beam-beam Simulation Code for Parallel Computers wiggler, cathode, gun, electron 509
 
  • A.C. Kabel, Y. Cai
    SLAC, Menlo Park, California
  We have developed a parallel simulation code allowing the self-consistent, three-dimensional simulation of the strong-strong beam-beam effect, using a particle-on-mesh technique and fast elliptic solvers. It is able to operate with sufficiently high logitudinal resolution to treat phase-averaging and hourglass effects in the interaction point (IP) correctly. This code has been generalized to handle the collisions of an arbitrary set of bunches at arbitrary positions in the ring (parasitic crossings), using appropriately reduced longitudinal resolution of collisions not in the design IP. We provide benchmarking results and parameter studies based on PEP-II.  
 
MOPLT032 Breakdown Resistance of Refractory Metals Compared to Copper lepton, wiggler, injection, undulator 614
 
  • M. Taborelli, S. Calatroni, M. Kildemo
    CERN, Geneva
  The behaviour of Mo, W and Cu with respect to electrical breakdown in ultra high vacuum has been investigated by means of a capacitor discharge method. The maximum stable electric field and the field enhancement factor, beta, have been measured between electrodes of the same material in a sphere/plane geometry for anode and cathode, respectively. The maximum stable field increases as a function of the number of breakdown events for W and Mo. In contrast, no systematic increase is observed for Cu. The highest values obtained are typically 500 MV/m for W, 350 MV/m for Mo and only 180 MV/m for Cu. This conditioning, found for the refractory metals, corresponds to a simultaneous decrease of beta and is therefore related to the field emission properties of the surface and their modification upon sparking. Accordingly, high beta values and no applicable field increase occur for Cu even after repeated breakdown. The results are in agreement with rf breakdown experiments [*] performed on prototype 30 GHz accelerating structures for the CLIC accelerator.

* W. Wuensch, C. Achard, S. Döbert, H. H. Braun, I. Syratchev, M. Taborelli, I. Wilson, "A Demonstration of High Gradient Acceleration", CERN-AB-2003-048-RF; CLIC-Note-569, Proc. PAC2003.

 
 
MOPLT033 Experimental Studies of Controlled Longitudinal Emittance Blow-up in the SPS as LHC Injector and LHC Test-Bed lepton, wiggler, injection, undulator 617
 
  • J. Tuckmantel, T. Bohl, T.P.R. Linnecar, E.N. Shaposhnikova
    CERN, Geneva
  The longitudinal emittance of the LHC beam must be increased in a controlled way both in the SPS and the LHC itself. In the first case a small increase is sufficient to help prevent coupled bunch instabilities but in the second a factor three is required to also reduce intra-beam scattering effects. This has been achieved in the SPS by exciting the beam at the synchrotron frequency through the phase loop of the main RF system using bandwidth-limited noise, a method that is particularly suitable for the LHC which will have only one RF system. We describe the tests that have been done in the SPS both for low and high intensity beams, the hardware used and the influence of parameters such as time of excitation, bandwidth, frequency and amplitude on the resulting blow-up. After taking into account intensity effects it was possible to achieve a controlled emittance increase by a factor of about 2.5 without particle loss or the creation of visible tails in the distribution.  
 
MOPLT034 Possible Causes and Consequences of Serious Failures of the LHC Machine Protection System lepton, wiggler, injection, undulator 620
 
  • J.A. Uythoven, R. Filippini, B. Goddard, M. Gyr, V. Kain, R. Schmidt, J. Wenninger
    CERN, Geneva
  The LHC machine protection systems, including the beam dumping system, are designed to ensure that failures leading to serious damage to the LHC during its lifetime are extremely unlikely. These kind of failures have to date been considered as being ?beyond the design case?, for instance requiring a combination of equipment failure and surveillance failure. However, they need to be evaluated to determine the required safety levels of the protection systems. A second objective is to understand if measures can and should be taken to further reduce the probability of such failures, or to minimise their impact. This paper considers various serious failure modes of the different machine protection systems. The probable consequences and possible ameliorating measures of the worst-case scenarios are discussed. The particular case of having a stored beam with an unavailable beam dumping system is mentioned, together with possible actions to be taken in such an event.  
 
MOPLT035 Beam Induced Heating of the SPS Fast Pulsed Magnets lepton, wiggler, undulator, dumping 623
 
  • J.A. Uythoven, G. Arduini, T. Bohl, F. Caspers, E.H.R. Gaxiola, T. Kroyer, M. Timmins, L. Vos
    CERN, Geneva
  Fast pulsed magnets with ferrite yokes are used in CERN?s SPS accelerator for beam injection, extraction and excitation for tune measurements. The impedance of the ferrite structures can provoke significant beam induced heating, especially for beams with high peak currents as for LHC operation, even beyond the Curie temperature. The expected heating in the different kicker systems for various operational modes is compared with beam measurements. Estimates of the beam induced power have been derived from measured beam spectra. A fast extraction kicker system has recently been equipped with a cooling system. The measured cooling performance is compared with data from laboratory setups and numerical simulations.  
 
MOPLT037 Simulation of Transient Beam-feedback Interaction with Application to the Extraction of the CNGS Beam from the SPS lepton, wiggler, feedback, undulator 626
 
  • E. Vogel, W. Höfle
    CERN, Geneva
  For actual and future high energy proton accelerators, such as the LHC, transverse feedback systems play an essential role in supplying the physics experiments with high intensity beams at low emittances. We developed a simulation model to study the interaction between beam and transverse feedback system in detail, bunch-by-bunch and turn-by-turn, considering the real technical implementation of the latter. A numerical model is used as the nonlinear behavior (saturation) and limited bandwidth of the feedback system, as well as the transient nature at injection and extraction, complicates the analysis. The model is applied to the practical case of the CNGS beam in the SPS accelerator. This beam will be ejected from the SPS in two batches causing residual oscillations by kicker ripples on the second batch. This second batch continues to circulate for some 1000 turns after the first batch has been extracted and oscillations are planned to be damped by the feedback system. It is shown how the model can be extended to the case of transients at injection (LHC), and to include coupled bunch instability effects.  
 
MOPLT117 An Electron Front End for the Fermilab Multi-species 8 GeV SCRF Linac acceleration, wiggler, electron, radiation 809
 
  • P. Piot, G.W. Foster
    Fermilab, Batavia, Illinois
  Fermilab is considering 8 GeV superconducting linac whose primary mission is to serve as an intense H- injector for the main injector. This accelerator is also planned to be used for accelerating various other species (e.g. electrons and muons). In the present paper we investigate the possibility of such a linac to accelerate a high brightness electron beam to ~7 GeV. We propose a design for the electron front end, based on a photoinjector, and consider the electron beam dynamics along the linac. Start-to-end simulations of the full accelerator for electrons are presented. Finally the potential applications of the such an electron beam are discussed.  
 
TUPKF017 Electrons Beam Dynamics of the 100 MeV Preinjector Helios for the SOLEIL Synchrotron positron, damping, focusing, plasma 997
 
  • A.S. Setty
    THALES, Colombes
  A 100 MeV electron linac is under construction, in order to inject into the booster synchrotron of SOLEIL. The linac is designed to work according to two operation modes : a short pulse mode (2 ns - 0,5 nC) and a long pulse mode (300 ns - 8 nC). Calculation of the beam dynamics, using our selfmade code PRODYN, has been carried out from the gun to the end of the linac. Special care has been taken on the gun design to avoid an overfocusing outcoming beam in order to obtain a final low emittance. Calculations results are given.  
 
TUPKF018 Surface Morphology at the Quench Site positron, damping, focusing, plasma 1000
 
  • S. Berry, C.Z. Antoine, M. Desmons
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  It has been demonstrated recently that local magnetic field enhancement can originate from roughness (e.g. steps at grain boundaries). We are willing to investigate if the quench observed in superconducting niobium cavities can be related to such morphological defects. We recently developed two kinds of tool. 1) A replica technique that allows to reproduce the internal surface of cavities (non destructive testing). 2) A morphological analysis tool. Classical roughness measurements are not adapted to determine local curvature radius.This paper describes a new topological approach aiming at a better characterization of the surface morphology. We also present results of this technique applied to replica taken from cavities at the quench site.  
 
TUPKF019 Recent Developments on Superconducting b035 and b015 Spoke Cavities at IPN for Low and Medium Energy Sections of Proton Linear Accelerators. positron, damping, focusing, plasma 1003
 
  • G. Olry, J.-L. Biarrotte, S. Blivet, S. Bousson, F. Chatelet, D. Gardès, N. Hammoudi, T. Junquera, J. Lesrel, C. Miélot, A.C. Müller, D. Ruffier, H. Saugnac, P. Szott, J.P. Thermeau
    IPN, Orsay
  Spoke cavities studies leaded by IPN-Orsay, for both XADS and EURISOL projects, are fully integrated within the 5th and 6th European Framework Programs. During 2003, several tests have been performed on the first b035 spoke cavity prototype. They have demonstrated the great potential of this type of cavity in term of RF performances (Eacc max=12.5 MV/m at T=4.2 K) and mechanical behavior (very low sensitivity to errors fabrication, good stiffness…). Following the upgrade of our cryogenic facility, we have tested, this spring, the cavity at 2 K. These new results will be presented in this paper. In parallel, the fabrication of a new spoke cavity (2-gap, 352 MHz, b015) has begun in January. While keeping the same geometry than that of the b035 cavity, we carried out significant changes on the coupler port and stiffening system designs. We report here in particular, RF calculations concerning the new location of the coupler port (in order to minimize losses due to magnetic field) and also, mechanical calculations about the new stiffening ring. Finally, we will present the preliminary thought on modular cryomodule which are based on the ?short? cryomodule concept used with the Quarter Wave Resonators for the SPIRAL-2 project.  
 
TUPKF020 Numerical Investigation on the ELETTRA 500 MHz Power Coupler positron, damping, focusing, plasma 1006
 
  • C. Pasotti, P. Craievich, A. Fabris, G. Penco, M. Svandrlik
    ELETTRA, Basovizza, Trieste
  • B. B. Baricevic
    DEEI, Trieste
  Due to the high input power required to feed a resonant cavity, the RF input coupler is a critical component for the reliability of an RF system. The 500 MHz RF input coupler for the ELETTRA cavities was specified for 150 kW input power. It is important to investigate the performance limits of the coupler in view of increasing RF power requirements. The coupler's maximum peak field and dissipation versus the input power have been studied by means of the numerical simulator HFSS. Possible improvements to the existing design have been investigated. The optimization has to take into consideration the following requirements: convenient power transmission efficiency, RF matching, suitable coupling coefficient, negligible perturbation on cavity voltage, moderate operating temperature and stress.  
 
TUPKF021 First Year of Operation of SUPER-3HC at ELETTRA positron, focusing, plasma, beamloading 1009
 
  • G. Penco, P. Craievich, A. Fabris, C. Pasotti, M. Svandrlik
    ELETTRA, Basovizza, Trieste
  Since July 2003 a superconducting third harmonic cavity has been in routine operation at ELETTRA. When the cavity is activated the stored electron bunches are lengthened by about a factor of three. The related longitudinal Landau damping has allowed first time operation at 320 mA, 2.0 GeV with a beam completely free of longitudinal coupled bunch instabilities. With the cavity active the lifetime at 320 mA, 2.0 GeV is three times the theoretical value for nominal bunch length. The increase in beam stability and lifetime contributed significantly to enhance the brightness and the integrated flux of the source. We will further discuss the operating experience with the superconducting cavity and the cryogenic system, analyzing the impact of the new system on machine operation and uptime. Finally we will also report on the characterization of the cavity performance for different filling patterns of the storage ring and relate the results to preliminary beam-cavity interaction studies.  
 
TUPKF022 Constructionand Testing of the Beta=0.31, 352 MHz Superconducting Half-wave Resonator for the SPES Project positron, focusing, plasma, beamloading 1012
 
  • A. Facco, W. Lu, F. Scarpa
    INFN/LNL, Legnaro, Padova
  • E. Chiaveri, R. Losito
    CERN, Geneva
  • V. Zviagintsev
    TRIUMF, Vancouver
  The interest in low- and medium- beta superconducting cavities is presently focused to future high intensity proton, deuteron and heavy ion linacs. A particular application is acceleration of cw and pulsed beams of variable q/A, which requires cavities with a small number of gaps and excellent mechanical stability. We have designed and constructed a 2 gap, 352 MHz SC half wave cavity aiming to similar characteristics and fitting the requirements of the intermediate-beta section of the LNL-SPES driver. The status of the project and the first test results will be presented.  
 
TUPKF023 Construction of a 161 MHz, beta=0.16 Superconducting QWR with Steering Correction for RIA positron, focusing, plasma, beamloading 1015
 
  • A. Facco, W. Lu, F. Scarpa
    INFN/LNL, Legnaro, Padova
  • E. Chiaveri, R. Losito
    CERN, Geneva
  • T.L. Grimm, W. Hartung, F. Marti, R.C. York
    NSCL, East Lansing, Michigan
  • V. Zviagintsev
    TRIUMF, Vancouver
  We have built a 161 MHz, b=0.16 superconducting Quarter Wave Resonator with steering correction for the low beta section of RIA. This bulk niobium, double wall cavity, compatible with both separate vacuum between beam line and cryostats or unified one, was designed in collaboration between MSU-NSCL and LNL. The design is suitable for extension to other frequencies, e.g. to obtain the 80 MHz, beta=0.085 cavity required in RIA. The shaped drift tube allows correction of the residual QWR steering that can cause emittance growth especially in light ions; this could make this resonator a good alternative to Half-Wave resonators in high intensity proton-deuteron linacs, like the SPES injector project at LNL. First test results will be presented.  
 
TUPKF024 Operation Experience with ALPI Nb/Cu Resonators positron, focusing, plasma, beamloading 1018
 
  • A.M. Porcellato, L. Bertazzo, M. De Lazzari, D. Giora, V. Palmieri, S. Stark, F. Stivanello
    INFN/LNL, Legnaro, Padova
  The refurbishing, by replacing the Pb superconducting film by Nb, of ALPI QW accelerating resonators was completed in 2003. All the 52 cavities are now in operation showing a large increase in the average accelerating field, which exceeds 4.5 MV/m (21 MV/m pick electrical surface field). The performance of renewed resonators has been increasing with time reaching 6MV/m in the last produced units. The increase in ALPI performance and the advantage in conditioning and setting time obtained by the upgrading process will be reported.  
 
TUPKF025 Superconducting Niobium Film for RF Applications positron, focusing, plasma, beamloading 1021
 
  • A. Cianchi, L. Catani, A. Cianchi, S. Tazzari
    INFN-Roma II, Roma
  • Y.H. Akhmadeev
    Institute of High Current Electronics, Tomsk
  • A. Andreone, G. Cifariello, E. Di Gennaro, G. Lamura
    Naples University Federico II, Napoli
  • J.L. Langner
    The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
  • R.R. Russo
    Università di Roma II Tor Vergata, Roma
  Thin niobium film coated copper RF cavities are an interesting possible alternative to bulk-Nb cavities since copper is much cheaper than niobium, it has higher thermal conductivity and a better mechanical stability. Unfortunately, the observed degradation of the quality factor with increased cavity voltage of sputtered accelerating cavities restricts their usage in future large linear accelerators needing gradients higher than 15MV/m. We are developing an alternate deposition technology, based on a cathodic arc system working in UHV conditions. Its main advantages compared to standard sputtering are the ionized state of the evaporated material, the absence of gases to sustain the discharge, the much higher energy of atoms reaching the substrate surface and the possibility of higher deposition rates. To ignite the arc we use a Nd-YAG pulsed laser focused on the cathode surface that provides a reliable and ultraclean trigger. Recent results on the characterization of niobium film samples produced under different conditions are presented showing that the technique can produce bulk-like films suitable for RF superconducting applications.  
 
TUPKF026 RF Tests of the Beta=0.5 Five Cell TRASCO Cavities positron, focusing, plasma, beamloading 1024
 
  • A. Bosotti, C. Pagani, P. Pierini
    INFN/LASA, Segrate (MI)
  • J.P. Charrier, B. Visentin
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • G. Ciovati, P. Kneisel
    Jefferson Lab, Newport News, Virginia
  Two complete 5 cell superconducting cavities at b=0.5 have been designed and fabricated. The cavities have been designed to minimize peak electric and magnetic fields, with a goal of 8.5 MV/m of accelerating gradient, at a Q > 5E9. The cavities are currently in the testing stage and the results of the vertical tests will be presented at this conference.  
 
TUPKF031 Non-resonant Accelerating System at the KEK-PS Booster positron, focusing, plasma, booster 1027
 
  • S. Ninomiya, M. Muto, M. Toda
    KEK, Ibaraki
  The non-resonant accelerating system for the KEK-PS booster accelerator has been constructed. The system has been operating since October 2003 without trouble. The accelerating gap in the system is loaded with magnetic cores of high permeability. The cores produce high resistive impedance at the gap. The power dissipated in the cores amounts to 50kW at 16kV accelerating voltage. It is removed by forced-air cooling system. At the last operation of the accelerator, with the help of new COD-correction system, the average beam intensity of the booster increased to 2.6E+12ppp, which is 30% higher than before.  
 
TUPKF032 COD Correction by Novel Back-leg at the KEK-PS Booster positron, focusing, plasma, booster 1030
 
  • S. Ninomiya, K. Satoh, H. Someya, M. Toda
    KEK, Ibaraki
  The COD correction is performed by using new driving system of back-leg windings. Two back-leg coils of the separate magnets are connected to make a closed circuit in which the induced voltages of the two magnets have opposite phases to each other. When the current source is inserted into the closed loop, the current drives the two magnets with opposite polarities. If the pair of magnets is properly selected, the current effectively corrects the orbit distortion. The selection rule of the pair is as follows; one is the magnet at the maximum distortion and the second magnet is that separated with the betatron phase of -90deg. The correction system at the KEK-PS Booster reduced the COD to less than 1/5 of that without correction, and increased the capture efficiency. The average beam intensity of our Booster is increased from 2E+12 to 2.6E+12ppp.  
 
TUPLT027 Status of the HITRAP Decelerator Linac at GSI electron, beamloading, antiproton, betatron 1201
 
  • C.A. Kitegi, A. Bechtold, U. Ratzinger, A. Schempp
    IAP, Frankfurt-am-Main
  • T. Beier, L. Dahl, C. Kozhuharov, W. Quint, M. Steck
    GSI, Darmstadt
  • S. Minaev
    ITEP, Moscow
  Within the European Network HITRAP (heavy Ion trap) trapped and cooled higly charged ions up to U92+ will become avilable for a variety of attractive experiments in atomic physics. Heavy ions are produced, accelerated and stripped in the GSI accelerator complex and are stored in the ESR down to 4 MeV/u. To be captured in HITRAP, ions have to be decelerated to energies below 6 keV/u. The decelerator proposed to achieve these energies is a combination of an IH Drift tube cavity operating in the H11(0) mode and a RFQ. The operating frequency is 108.408MHz . The A/q range of the linac is up to 3. A very efficient deceleration by up to 11 MV along the 2.7 m long IH cavity with a rf power of 200kw is achieved by applying the KONUS beam dynamics. The deceleration from 500 A.keV down 6A.keV is provided by a 1.8 m long 4-rod RFQ.The beam dynamics as well as the cavity design of that linac will be described.The decelerator linac will be installed in the reinjection beam line and is being developed in collaboration between GSI and the Frankfurt University .  
 
TUPLT028 Development of Finger Drift Tube Linacs electron, focusing, beamloading, antiproton 1204
 
  • K.-U. Kuehnel, A. Schempp
    IAP, Frankfurt-am-Main
  • C.P. Welsch
    MPI-K, Heidelberg
  At higher particle energies the efficiency of RFQs decreases and DTL structures in combination with magnetic quadrupoles are used. One approach at IAP is the combination of RFQ and DTL. To compensate the defocusing effects of a DTL structure, the accelerating gaps of a spiral loaded cavity were equiped with small focusing fingers. These fingers arranged in a quadrupole symmetry provide an additional focusing field component. The beam dynamics of such a cavity has been studied with PARMTEQ. Simulations of the rf properties have been done using microwave studio. A prototype of a spiral loaded cavity with finger drift tubes has been built and low power measurement were made. Results of the calculations as well as low level and bead pertubation measurements are presented in this contribution.  
 
TUPLT029 Status of the Superconducting D+-CH-DTL Design for IFMIF electron, focusing, beamloading, antiproton 1207
 
  • A.C. Sauer, H. Deitinghoff, H. Klein, H. Liebermann, O. Meusel, H. Podlech, U. Ratzinger, R. Tiede
    IAP, Frankfurt-am-Main
  Within the IFMIF project (International Fusion Materials Irradiation Facility) a high current D+-linac operated in cw mode has to be developed. The acceleration of a 125 mA D+-beam from 0.1 MeV up to 40 MeV must be performed at an extremely low loss rate (0.1-0.2 microA/m). One optional layout of the acceleration facility consists of a high current ion source, low energy beam transport (LEBT), Radio-Frequency-Quadrupol (RFQ) followed by a superconducting H-type DTL. The matching of the beam between subsequent linac sections has to be carefully optimized to avoid an activation of the structures. Actual beam dynamics simulations for such a linac design including parameter errors of components are reported. Consequences for the LEBT- and RFQ-section are discussed.  
 
TUPLT030 Numerical Simulations for the Frankfurt Funneling Experiment electron, ion, focusing, beamloading 1210
 
  • J. Thibus, A. Schempp
    IAP, Frankfurt-am-Main
  High beam currents are necessary for heavy ion driven fusion (HIF) or XADS. To achieve these high beam currents several ion beams are combined at low energies to one beam using the funneling technique. In each stage a r.f. funneling deflector bunches two accelerated beam lines to a common beam axis. The Frankfurt Funneling Experiment is a scaled model of the first stage of a HIF driver consisting of a Two-Beam RFQ accelerator and a funneling deflector. Our two different deflectors have to be enhanced to reduce particle losses during the funneling process. This is done with our new developed 3D simulation software DEFGEN and DEFTRA. DEFGEN generates the structure matrix and the potential distribution matrix with a Laplace 3D-solver. DEFTRA simulates ion beam bunches through the r.f. deflector. The results of the simulations of the two existing deflectors and proposals of new deflector structures will be presented.  
 
TUPLT032 The Frankfurt Funneling Experiment electron, focusing, beamloading, antiproton 1213
 
  • H. Zimmermann, U. Bartz, N. Mueller, A. Schempp, J. Thibus
    IAP, Frankfurt-am-Main
  The Frankfurt Funneling Experiment is a scaled model of the first funneling stage of a HIF driver to gather experiences in the funneling technique. It is a procedure to multiply beam currents at low energies in several stages. In each stage two beam lines are combined to a common beam line. The funneling technique is required for new proposed high current accelerator facilities like HIDIF. The main goal is to prevent emittance growth during the funneling process. Our experiment consists of two ion sources, a Two-Beam RFQ accelerator, two different funneling deflectors and a beam diagnostic equipment system. We have demonstrated the principle of funneling with both deflector types. But the measurements have shown a bad matching of the RFQ to the funneling deflector. Now with our new RFQ electrode design we achieve a special three dimensional matching to the deflector. The new results of our measurements and simulations will be presented.  
 
TUPLT044 Delta-T Procedure for Superconducting Linear Accelerator ion, beamloading, antiproton, damping 1249
 
  • A. Bogdanov, R. Maier, Y. Senichev
    FZJ/IKP, Jülich
  Development of the tune-up procedure for a linear accelerator is the next important stage after the design is complete. Conventional delta-T procedure developed for tuning of a normal-conducting linear accelerator by Crandall allows setting up of accelerating field amplitude and phase in cavity with known phase velocity. However, application of the delta-T procedure to a superconducting linac meets some difficulties. In particular, the synchronous phase velocity in superconducting linac is determined by RF phase shift between cavities, but not by geometrical size of accelerating cells as in normal conducting linac. Additionally, in superconducting linac the smaller phase advance leads to an insensibility of particles at the cavity exit to the variation of the electric field inside the cavity. In the paper we consider the modified delta-T procedure adjusted for superconducting linac. Numerical simulations prove that by proposed technique both tasks of preservation of necessary stable region motion and providing the beam with required final energy can be successfully solved.  
 
TUPLT070 Study of a Linac Booster for Proton Therapy in the 30-62 MeV Energy Range injection, laser, beamloading, antiproton 1312
 
  • V.G. Vaccaro, A. D'Elia, M.R. Masullo
    Naples University Federico II and INFN, Napoli
  • D. Capasso, S. Lanzone
    Naples University Federico II, Napoli
  • T. Clauser, A. Rainò
    INFN-Bari, Bari
  • C. De Martinis, D. Giove, M. Mauri
    INFN/LASA, Segrate (MI)
  • V. Variale
    Bari University, Science Faculty, Bari
  Recent results in accelerator physics have shown the feasibility of a coupling scheme between a cyclotron and a linac for proton acceleration. Cyclotrons with energies up to 30 MeV, mainly devoted to radioisotopes production, are available in a large number of medical centres. These two evidences have suggested the idea to study and design a linac booster able to increase the initial proton energy up to the values required for the treatment of tumors, like the ocular ones. The main challenge in such a project is related to meet the requirements arising from the beam dynamics with the constrains due both to the mechanical structures and tolerances and to the heat dissipation mechanism chosen in the design. In this paper we will review the rationale of the project and we will discuss the basic design of a compact 3 Ghz linac with a new approach to the cavities used in a SCL (Side Coupled Linac) structure  
 
TUPLT074 Dark Current Reduction System for SPring-8 Linac injection, laser, beamloading, antiproton 1324
 
  • T. Kobayashi, T. Asaka, H. Hanaki, M. Shoji, S. Suzuki, K. Tamura
    JASRI/SPring-8, Hyogo
  The SPring-8 linac accelerates dark currents generated by its injector part up to 1 GeV. These dark currents are injected with main beam into the SPring-8 storage ring and then spoil the purity of the stored beam. The dark currents are mainly composed of a grid emission current from a thermionic gun and field emission currents from rf accelerating structures. A beam deflector for kicking only the grid emission by a pulsed electric field was developed and installed in the SPring-8 linac. We observed that the beam deflector greatly reduced the grid emission current accelerated up to 1 GeV. The measured purity of the stored single-bunched beam was about 5x10-6 when the deflector operated, which was almost 1/100 of the purity without filtering by the deflector. However, the deflector, which is installed before the prebucher, cannot reduced the field emission currents from the buncher cavities and the first acccelerating structure. These dark currents take considerable proportion of the total dark currents observed at the end of the linac. We are trying to spin off the field emission currents by weak magnetic fields across the accelerating structure generated by several coils.  
 
TUPLT080 Design of the Beam Transportation Line from the Linac to the 3-GeV RCS for J-PARC septum, sextupole, booster, laser 1342
 
  • T. Ohkawa
    JAERI, Ibaraki-ken
  • M. Ikegami
    KEK, Ibaraki
  L3BT is beam transportation line from the linac to the 3-GeV RCS which is the part of the accelerators for the High-Intensity Proton Accelerator Facility Project, J-PARC. For the requirement of the beam loss minimization, the L3BT does not only connect the linac to the 3GeV RCS, but also modifies the linac beam to the acceptable shape for the 3-GeV RCS. The required beam parameters at the injection point of the RCS are momentum spread < ±0.1% (100%)and transverse emittance < 4pmm.mrad (99%). To achieve these beam qualities, the L3BT should have following functions: momentum compaction, halo scraping and beam diagnostics. In this paper, results of the design and beam simulation of the L3BT are presented.  
 
TUPLT081 Lattice Design of Large Acceptance FFAGs for the PRISM Project septum, sextupole, booster, laser 1345
 
  • A. Sato
    Osaka University, Osaka
  • S. Machida
    KEK, Ibaraki
  In order to realize a super muon beam that combines high-intensity, low-energy, narrow energy-spread and high purity, the PRISM project has been proposed. In this project, a FFAG ring is used as a phase rotator. In this paper, a method of designing the PRISM-FFAG lattice will be described. The PRISM-FFAG has to have both of large transverse acceptance and large momentum acceptance to achieve high intensity. Furthermore, long straight sections to install RF cavities are required to obtain a high surviving ratio of the muon. Therefore, the PRISM-FFAG requires its magnets to have large aperture and small opening angle. In such magnets, not only nonlinear effects but also magnetic fringing field are important to study the beam dynamics of FFAGs. Although using realistic 3D magnetic field maps made with programs such as TOSCA is the best solution to study the FFAG dynamics, it takes long time to make such field maps. On a design process of the PRISM-FFAG, quasi-realistic 3D magnetic field maps, which are calculated applying spline interpolation to POISSON 2D field, were used to study the beam dynamics. A program based on GEANT3.21 was used for particle tracking.  
 
TUPLT111 RF Focusing of Low-Charge-to-Mass-Ratio Heavy-Ions in a Superconducting Linac electron, focusing, gun, booster 1405
 
  • E.S. Masunov, D.A. Efimov
    MEPhI, Moscow
  • P.N. Ostroumov
    ANL/Phys, Argonne, Illinois
  A post-accelerator of radioactive ions (RIB linac) must produce high-quality beams over the full mass range, including uranium, with high transmission and efficiency (P.N. Ostroumov and et al., Proc. of the PAC2001, p. 4080.). The initial section of the RIB linac is a low-charge-to-mass-ratio superconducting RF linac which will accelerate any ion with q/A>=1/66 to ~900 keV/u or higher. This section of the linac consists of many interdigital cavities operating at –20 degree synchronous phase and focusing can be provided by SC solenoids following each cavity. For the charge-to-mass ratio q/A=1/66 a proper focusing can be reached with the help of strong SC solenoid lenses with magnetic fields up to 15 T. These state-of-the-art solenoids are expensive. A possible lower cost alternative focusing method based on the combination of low-field SC solenoids and RF focusing is proposed and discussed in this paper.  
 
TUPLT112 Radiation Damage to the Elements of the Nuclotron-type Dipole of SIS100 electron, focusing, gun, booster 1408
 
  • E. Mustafin, G. Moritz, G. Walter
    GSI, Darmstadt
  • L. Latysheva, N. Sobolevskiy
    RAS/INR, Moscow
  Radiation damage to various elements of the Nuclotron-type dipole of SIS100 sensitive to irradiation was calculated. Among the elements of consideration were the superconducting cables, insulating materials, ceramic insertions and high-current by-pass diodes. The Monte-Carlo particle transport code SHIELD was used to simulate propagation of the lost ions and protons together with the products of nuclear interactions in the material of the elements. The results for the proton projectiles were cross-checked using the particle transport code MARS, and a good agreement between the codes were found. It was found that the lifetime of the organic materials under irradiation are much more restrictive limit for the tolerable level of beam particle losses than the danger of the quench events.  
 
TUPLT113 Technicalities for a Novel Medium Energy Ion Accelerator electron, focusing, gun, ion 1411
 
  • V. Gorev
    RRC Kurchatov Institute, Moscow
  Transmutation of radioactive waste,high-intensity pulsed sources of fast neutrons,problem of inertially-confined fusion and a lot of different problems of science and technology put increased demands on the linear high power medium energy proton and heavy ion accelerators.But these accelerators are presently massive,huge and very expansive,which restrict now and in a near future their wide use and motivates the study of altenetive methods to achieve the design current,power and economic characteristics.This report decribes the present reseach on attaining high power medium energy ion beams,using novel idea for accelerator design.Theoretical proposal and preliminary conceptual design for the accelerator,based on a principle of free flying ion emitter("ballistic anode"),were discussed first a few years ago.The principle involves a high potencial difference generated only for a short time in the special vacuum chamber,but not steady-state conditions.Now,we would like to discuss next problems:1.technicalities of the ballistic anode design,both for proton and heavy ion beams generation.2 pulse power multiplication.3.high current sources for charge pumping of the ballistic anode.4 experimental modelling.  
 
TUPLT117 Test of Materials for the High Temperature Intense Neutron Target Converter focusing, gun, ion, booster 1413
 
  • K. Gubin, M. Avilov, S. Fadeev, A. Korchagin, A. Lavrukhin, P.V. Logatchev, P. Martyshkin, S.N. Morozov, S. Shiyankov
    BINP SB RAS, Novosibirsk
  • J. Esposito, L.B. Tecchio
    INFN/LNL, Legnaro, Padova
  Nowadays in LNL INFN (Italy) the project for gain and study of short-lived radioactive isotopes is in progress [1]. The intense neutron target is required for these goals. In BINP, Russia, the design of high temperature target cooled by radiation is proposed. Presented paper describes the results of preliminary test of materials for the target converter: MPG6-brand graphite, graphite material on the basis of 13C, boron carbide, glassy carbon. Test included the distributed heating over volume of samples with the electron beam up to conditions, simulating the converter working regime (heating power density up to 1300 W/cm2, temperature up to 20000C, temperature gradient up to 1000C/mm). Graphite materials show its adaptability under conditions specified.  
 
TUPLT118 Test of Construction for High Temperature Intense Neutron Target Prototype focusing, gun, ion, booster 1416
 
  • K. Gubin, M. Avilov, D. Bolkhovityanov, S. Fadeev, A. Lavrukhin, P.V. Logatchev, P. Martyshkin, A.A. Starostenko
    BINP SB RAS, Novosibirsk
  • O. Alyakrinsky, L.B. Tecchio
    INFN/LNL, Legnaro, Padova
  Within the framework of the creation of the high temperature intense neutron target prototype, the thermal tests of the preliminary design were done in BINP. Tests were aimed at experimental definition of temperature and heat flux distribution over the construction, heat transfer via the contact areas between materials selected, specifying the properties of these materials. This paper presents the experimental test results as well as the comparison of experimental data with the results of numerical simulation of the working regimes of the construction.  
 
TUPLT120 Commissioning of Electron Cooler EC-300 electron, focusing, gun, ion 1419
 
  • V.B. Reva, E.A. Bekhtenev, V.N. Bocharov, A.V. Bubley, Y. Evtushenko, A.D. Goncharov, A.V. Ivanov, V.I. Kokoulin, V.V. Kolmogorov, M.N. Kondaurov, S.G. Konstantinov, V.R. Kozak, G.S. Krainov, Ya.G. Kruchkov, E.A. Kuper, A.S. Medvedko, L.A. Mironenko, V.M. Panasyuk, V.V. Parkhomchuk, K.K. Schreiner, B.A. Skarbo, A.N. Skrinsky, B.M. Smirnov, M.A. Vedenev, R. Voskoboinikov, M.N. Zakhvatkin, N.P. Zapiatkin
    BINP SB RAS, Novosibirsk
  • J. Li, W. Lu, L.J. Mao, Z.X. Wang, X.B. Yan, X.D. Yang, J.H. Zhang, W. Zhang, H.W. Zhao
    IMP, Lanzhou
  The article deals with the commissioning of electron cooler EC-300. It was designed and manufactured for CSR experiment (IMP, Lanzhou, China) by BINP, Russia. The energy of electron beam is up to 300 keV, the electron current is up to 3 A, the magnetic field in the cooling section is up to 1.5 kG. The major innovation of the cooler is the variable profile of electron beam, the electrostatic bends of the electron beam and the system of the magnetic field correction. During commissioning the linearity of the magnetic field 10-6 was obtained, the recuperation efficiency was observed up 10-6 , the pressure of residual gas in the vacuum chamber was 5? 10-11 torr during operation with the electron beam. The CSRe cooler for IMP is a new step at cooling technique and the first results achieved during commissioning are very interesting for accelerator physics.  
 
TUPLT121 Compact Tandem Accelerator Based Neutron Source for the Medicine electron, focusing, gun, booster 1422
 
  • V.V. Shirokov, A.A. Babkin, P.V. Bykov, G.S. Kraynov, G. Silvestrov, Y. Tokarev
    BINP SB RAS, Novosibirsk
  • M.V. Bokhovko, O.E. Kononov, V.N. Kononov
    IPPE, Kaluga Region
  Status of original heavy hydrogen ion electrostatic accelerator-tandem is described. Potential electrodes with vacuum insulation organize tract for accelerating ion beam before and after gas stripper, located inside the high voltage electrode. There are no accelerating tubes in the tandem proposed. 20 kHz, 10 kW, 500 kV compact sectioned rectifier is a high voltage source. Both the geometry of neutron source and results of the rectifier testing are presented. Estimation of yield and space-energy distribution of neutron, as a result of nuclear reactions produced by heavy hydrogen ion in beryllium or carbon targets are given. Result of Monte-Carlo simulation of neutron and photon transferring for these sources of neutron is the distribution of the absorbed dose incide phantom. Result of the simulation are compared with result of the experiment. The possibility of use of this neutron source for the neutron or neutron capture therapy is discussed too.  
 
TUPLT124 DESIREE - A Double Electrostatic Storage Ring electron, focusing, gun, booster 1425
 
  • K.-G. Rensfelt, G. Andler, L. Bagge, M. Blom, H. Danared, A. Källberg, S. Leontein, L. Liljeby, P. Löfgren, A. Paal, A. Simonsson, Ö. Skeppstedt
    MSL, Stockholm
  • H. Cederquist, M. Larsson, H. Schmidt, K. Schmidt
    Stockholm University, Department of Physics, Stockholm
  The advantages of storage rings with only electrostatic elements were first demonstrated by ELISA in Aarhus and later in other places. At MSL and Fysikum at Stockholm University the ideas have been developed further in the Double Electrostatic Storage Ion Ring ExpEriment, DESIREE. Beams of negative and positive ions will be merged in a common straight section of the rings so that low energy collisions can be studied. Furthermore the rings will be cooled to 10 - 20 K in order to relax internal excitations in circulating molecules. A design report can be found at www.msl.se. The project is now (January 2004) almost fully financed and the final design work has recently been started. The paper will shortly review the physics programme and describe the status of the design work.  
 
TUPLT128 The Operation Modes of Kharkov X-ray Generator based on Compton Scattering NESTOR laser, focusing, gun, booster 1428
 
  • A.Y. Zelinsky, E.V. Bulyak, P. Gladkikh, I.M. Karnaukhov, A. Mytsykov, A.A. Shcherbakov
    NSC/KIPT, Kharkov
  • T.R. Tatchyn
    SLAC/SSRL, Menlo Park, California
  The results of theoretical and numerical considerations of linear Compton scattering are used to evaluate characteristics of X-rays produced by collision between a low emittance electron beam and intensive laser light in an X-rays generator NESTOR of NSC KIPT. Two main generation modes have been under consideration at preliminary NESTOR design. There are the operation mode for medicine 33.4 keV X-rays production using 43 Mev electron beam and Nd:YAG laser beam and higher energy X-rays production mode providing X-rays with energy up to 900 keV with 225 MeV electron beam and Nd:YAG laser beam. It is supposed to use an optical cavity for laser beam accumulation of about 2.6 m long and an interaction angle of about 30 in both operation modes. A few more operation modes provide possibility to expand operation range of NESTOR. Using interaction angle 100 and 1500 along with optical resonator 42 or 21 cm long and the second mode of laser light it is possible to produce X-rays in energy range from a few keV till 1.5 MeV. The intensity and spectral brightness of the X-rays is expected to be ~ 1013 phot/s and ~ 1013 phot/s/mm2/mrad2/0.01%BW respectively.  
 
TUPLT129 NESTOR Reference Orbit Correction focusing, gun, booster, optics 1431
 
  • V.A. Ivashchenko, P. Gladkikh, I.M. Karnaukhov, A. Mytsykov, V.I. Trotsenko, A.Y. Zelinsky
    NSC/KIPT, Kharkov
  It is known that intensity of scattered radiation in X-rays generators based on Compton scattering strongly depends on relative position of electron and laser beams. For this reason it is very important to have effective system of reference orbit correction and beam position control as well along whole ring as at the interaction point. In the paper the results of design and development of reference orbit correction system for compact storage ring NESTOR are presented. The total reference orbit correction will be carried out in vertical plane only. Correctors will be disposed on quadrupole lenses and will be provide reference orbit correction angle up to 0.10. The local correction at the interaction point will be provided with four correctors located at the interaction straight section. In the article results of calculations, layout of whole system, quadrupole lenses and pick-up station parameters and schemes are presented.  
 
TUPLT132 Investigation of Injection through Bending Magnet Fringe Fields in X-rays Source NESTOR gun, booster, optics, injection 1434
 
  • A. Mytsykov, P. Gladkikh, A.V. Rezaev, A.Y. Zelinsky
    NSC/KIPT, Kharkov
  In paper injection in the X-rays source NESTOR through fringe fields of a bending magnet is considered. The simulation of a motion of a beam of charged particles through 3-d fields of magnetic devices of the injection channel, which ones is located on a ring, are performed. The focusing properties of the injection channel are determined.  
 
TUPLT133 Test Results of Injector Based on Resonance System with Evanescent Oscillations booster, bunching, optics, injection 1437
 
  • S.A. Perezhogin, M.I. Ayzatskiy, E.Z. Biller, K. Kramarenko, V.A. Kushnir, V.V. Mytrochenko, Z.V. Zhiglo
    NSC/KIPT, Kharkov
  Report presents results of tune-up and tests of the compact electron S ? band injector consisting of the low-voltage diode electron gun and the bunching system based on the resonant system with the evanescent oscillation. In the considered bunching system electrical field increased from beam entrance to an exit of the buncher. The injector designed for bunching of electron beam with initial energy of 25 keV and pulse current of 300 mA and accelerating it to the energy of 1 MeV.  
 
TUPLT134 Lattice of NSC KIPT Compact Intense X-ray Generator NESTOR electron, booster, bunching, optics 1440
 
  • A.Y. Zelinsky, P. Gladkikh, I.M. Karnaukhov, V. Markov, A. Mytsykov, A.A. Shcherbakov
    NSC/KIPT, Kharkov
  The new generation of the intense X-rays sources based on low energy electron storage ring and Compton scattering of laser beam allows to produce X-rays with intensity up to 1014 phot/s. One of the main traits of a storage ring lattice for such generator type is using of magnetic elements with combined focusing functions such as bending magnets with quadrupole and sextupole field components. In combination with very low bending radius and dense magnetic elements setting along ring circumference it leads to increasing of 3D magnetic field effects on electron beam dynamics and can decrease generated radiation intensity drastically. For the reasons of very low electron beam size at the interaction point and strong focusing in a compact storage ring the questions of determination of accuracy of bending magnet is very important too. The paper is devoted to the description of lattice of NSC KIPT Compact X-ray generator NESTOR. The results of investigations of the effects of 3D magnetic field and harmonic compound due to manufacture errors of bending magnets, bending magnet and lenses edges on electron beam dynamics are presented.  
 
TUPLT136 Proton Beam Line for the ISIS Second Target Station target, electron, booster, bunching 1443
 
  • D.J. Adams
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  The ISIS facility, based at the Rutherford Appleton Laboratory in the UK, is an intense pulsed source of Muons and Neutrons used for condensed matter research. The accelerator facility delivers an 800 MeV proton beam of 2.5x1013 protons per pulse at 50 Hz. As part of the facility upgrade, which includes increasing the source intensity to 3.7x1013 protons per pulse using a dual harmonic RF system, it is planned to share the source with a second, 10 Hz, target station. A beam line supplying this target will extract from the existing target station beam line. Measurements and models characterising the optical functions around the extraction point of the existing line are discussed. The optical design, diagnostics and beam correction systems for second target station beam line are presented.  
 
TUPLT137 Comparative Simulation Studies of Electron Cloud Build-up for ISIS and Future Upgrades target, bunching, optics, injection 1446
 
  • G. Bellodi
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  Electron cloud effects currently limit the performance of several proton accelerators operating with high beam current. Although ISIS, the 160 kW 70-800 MeV proton synchrotron at the Rutherford Appleton Laboratory (UK), has never appeared to be affected by the problem in its 15 years of operations, e-p instabilities could potentially be a cause of concern for future machine upgrades to higher beam powers. In this paper we review the present status of simulations for ISIS and compare it to preliminary results for two upgrade options: a 0.5MW 180-800 MeV scheme and a 1MW 0.8-3 GeV scheme with an additional synchrotron using ISIS as a booster (see C. Prior et al., ISIS megawatt upgrade plans, in Proceedings of the 2003 Particle Accelerator Conference PAC 2003, Portland, Or, USA).  
 
TUPLT167 Installation of the Spallation Neutron Source (SNS) Warm Linac focusing, bunching, betatron, injection 1521
 
  • P.E. Gibson, C. Deibele, J.J. Error, G.A.J. Johnson, P. Ladd
    ORNL/SNS, Oak Ridge, Tennessee
  • N.K. Bultman
    LANL, Los Alamos, New Mexico
  The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built at Oak Ridge National Laboratory. The SNS project design and construction is a partnership involving six DOE national laboratories including Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Oak Ridge, and Los Alamos. When completed in 2006, the SNS will provide the most intense, pulsed neutron beams in the world for scientific research and industrial development. At the present time we are installing and commissioning the warm linac system, designed by Los Alamos, and have to date had good success. The warm linac is comprised of six Drift Tube Linac (DTL) tanks and four Coupled Cavity Linac (CCL) modules. These accept an incoming negative hydrogen ion beam from the Front End injector at 2.5 MeV, and accelerate to a final energy of 185 MeV. At this time we have installed and commissioned DTL tanks 1-3 and installed CCL module 1 . Experience and information gained during installation will be presented. The performance in terms of alignment, vacuum and field tuning will be described.  
 
TUPLT168 SNS Beam Commisioning Status focusing, bunching, betatron, injection 1524
 
  • S. Henderson, A.V. Aleksandrov, S. Assadi, W. Blokland, C. Chu, S.M. Cousineau, V.V. Danilov, G.W. Dodson, J. Galambos, M. Giannella, D.-O. Jeon, S. Kim, L.V. Kravchuk, M.P. Stockli, E. Tanke, R.F. Welton, T.L. Williams
    ORNL/SNS, Oak Ridge, Tennessee
  The Spallation Neutron Source accelerator systems will provide a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron production. The accelerator complex consists of an H- injector capable of producing 38 mA peak current, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The linear accelerator consists of a Drift Tube Linac, a Coupled-Cavity Linac and a Superconducting Linac which provide 1.5 mA average current to the accumulator ring. The staged beam commissioning of the accelerator complex is proceeding as component installation progresses. In three separate beam commissioning runs, the H- injector and Drift Tube Linac tanks 1-3 have been commissioned at ORNL. Several important performance goals have been achieved, namely 38 mA peak beam current, 1 msec beam pulse length and 1 mA average beam current. Results and status of the beam commissioning program will be presented.  
 
WEPLT145 Beam Loss Studies in High-intensity Heavy-ion Linacs sextupole, laser, resonance, target 2173
 
  • P.N. Ostroumov, V.N. Aseev, E.S. Lessner, B. Mustapha
    ANL/Phys, Argonne, Illinois
  A low beam-loss budget is an essential requirement for high-intensity machines and represents one of their major design challenges. In a high-intensity heavy-ion machine, losses are required to be below 1 W/m for hands-on-maintenance. The driver linac of the Rare Isotope Accelerator (RIA) is designed to accelerate beams of any ion to energies from 400 MeV per nucleon for uranium up to 950 MeV for protons with a beam power of up to 400 kW. The high intensity of the heaviest ions is achieved by acceleration of multiple-charge-state beams, which requires a careful beam dynamics optimization to minimize effective emittance growth and beam halo formation. For beam loss simulation purposes, large number of particles must be tracked through the linac. Therefore the computer code TRACK [P.N. Ostroumov and K.W. Shepard, PRST AB 11, 030101 (2001)] has been parallelized and calculations is being performed on the JAZZ cluster [*] recently inaugurated at ANL. This paper discusses how this powerful tool is being used for simulations for the RIA project to help decide on the high-performance and cost-effective design of the driver linac.

* The Jazz Cluster, http://www.lcrc.anl.gov/jazz

 
 
WEPLT146 Mismatch Oscillations in High-current Accelerators sextupole, laser, resonance, target 2176
 
  • O.A. Anderson
    LBNL, Berkeley, California
  Strong space charge challenges the designers of modern accelerators such as those used in Heavy Ion Inertial Fusion. Simple, accurate design tools are useful for predicting beam behavior, such as phase advances and envelope oscillation periods, given the beam emittance and charge and the lattice parameters. Along with the KV beam model, the smooth approximation [*] is often used. It is simple but not very accurate in many cases. Although Struckmieir and Reiser [**] showed that the stable envelope oscillations of unbalanced beams could be obtained accurately, they used a hybrid approach where the phase advances σ0 and σ were already known precisely. When starting instead with basic quantities–quadrupole dimensions, field strength, beam line charge and emittance–the smooth approximation formulas give substantial errors (10% or more). We previously described an integration method [***] for matched beams that yields fairly simple third-order formulas for σ0, σ, beam radius and ripple. Here we extend the method to include small-amplitude mismatch oscillations. We derive a simple modification of the smooth approximation formulas and show that it improves the accuracy of the predicted envelope frequencies significantly–for example, by a factor of five when σ0 is 83 degrees.

* M. Reiser, Particle Accelerators 8, 167 (1978) ** J. Struckmeier and M. Reiser, Particle Accelerators 14, 227 (1984)*** O. A. Anderson, Particle Accelerators 52, 133 (1996)

 
 
WEPLT147 Lattice Studies for CIRCE (Coherent InfraRed CEnter) at the ALS sextupole, laser, resonance, target 2179
 
  • H. Nishimura, D. Robin, F. Sannibale, W. Wan
    LBNL, Berkeley, California
  CIRCE (Coherent InfraRed Center) at the Advanced Light Source is a proposal for a new electron storage ring optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range. One of the main requirement for this special mode of operation is the capability of the ring of operating at very small momentum compaction values. In this regime, the longitudinal dynamics becomes strongly nonlinear and an accurate control of the higher order energy dependent terms of the momentum compaction is necessary. The lattice for CIRCE allows controlling these terms up to the third order. The paper describes the lattice and presents the calculated performances in terms of momentum acceptance, dynamic aperture, lifetime and momentum compaction tune capabilities.  
 
WEPLT148 Dynamical Map for Combined Function Magnets with Solenoid, Dipole and Quadrupole Fields sextupole, laser, resonance, target 2182
 
  • A. Wolski, M. Venturini
    LBNL, Berkeley, California
  The interaction regions of colliders invariably include strong solenoid fields. Where quadrupoles and dipoles are embedded in the solenoid, the beam dynamics in the combined fields can be complicated to model using the traditional approach of interleaving slices of different fields. The complexity increases if the design trajectory is offset from the magnetic axis; this is the case, for example, in PEP-II. In this paper, we present maps for combined solenoid, dipole and quadrupole fields that provide a much simpler alternative to the traditional approach, and show that the deviation of the design trajectory from the magnetic axis can be handled in a straightforward manner. We illustrate the techniques presented by reference to the PEP-II interaction region.  
 
WEPLT149 Image-charge Effects on the Beam Halo Formation and Beam Loss in a Small-aperture Alternating-gradient Focusing System sextupole, laser, resonance, focusing 2185
 
  • J. Zhou, C. Chen
    MIT/PSFC, Cambridge, Massachusetts
  The image-charge effects on an intense charged-particle beam propagating through an alternating-gradient focusing channel with a small aperture, circular, perfectly conducting pipe are studied using a test-particle model. For a well-matched elliptical beam with the Kapchinskij-Vladimirskij (KV) distribution, it is found that halo formation and beam loss is induced by nonlinear fields due to image charges on the wall. The halo formation and chaotic particle motion dependent sensitively on the system parameters: filling factor of the quadrupole focusing field, vacuum phase advance, beam perveance, and the ratio of the beam size to the aperture. Furthermore, the percentage of beam loss to the conductor wall is calculated as a function of propagating distance and aperture. The theoretical results are compared with PIC code simulation results.  
 
WEPLT151 Using the PBO LAB(TM) Optimization and Transport Modules to Gain an Improved Understanding of the LLUMC Proton Therapy Beamlines sextupole, optics, proton, laser 2188
 
  • G.H. Gillespie, O.V. Voronkova
    G.H. Gillespie Associates, Inc., Del Mar, California
  • G. Coutrakon, J. Hubbard, E. Sanders
    LLU/MC, Loma Linda, California
  The Particle Beam Optics Laboratory (PBO Lab) has an advanced Optimization Module that works in concert with beam optics codes (also modules in PBO Lab) to solve optimization and fitting problems that are difficult or impossible to address with optics code alone. The PBO Lab Optimization Module has been used in conjunction with the TRANSPORT Module to study the beamlines of the proton therapy center at the Loma Linda University Medical Center (LLUMC). The primary goal of the study was to establish a fast, efficient and reliable procedure for determining the parameters of the beam extracted from the synchrotron accelerator that best fit the extensive wire scanner profile data used to monitor the LLUMC proton therapy beamlines. This paper summarizes how the PBO Lab Optimization Module is applied to this problem and presents selected results from the LLUMC proton therapy beamline study.  
 
WEPLT152 Experimental Results of the Small Isochronous Ring sextupole, optics, proton, laser 2191
 
  • J.A. Rodriguez, F. Marti, R.C. York
    NSCL, East Lansing, Michigan
  • E. Pozdeyev
    Jefferson Lab, Newport News, Virginia
  The Small Isochronous Ring (SIR) has been in operation since December 2003. The main purpose of this ring, developed and built at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU), is to simulate the dynamics of intense beams in large accelerators. To observe the same effects, the beam power needed in SIR is orders of magnitude lower and the time scale is much longer than in the full scale machines. These differences simplify the design and operation of the accelerator. The ring measurements can be used to validate the results of space charge codes. After a variable number of turns, the injected hydrogen bunch (with energies up to 30 keV) is extracted and its longitudinal profile is measured using a fast Faraday cup. We present a summary of the design, the results of the first six months of operation and the comparison with selected space charge codes.  
 
THPKF002 Linac RF Control System for CANDLE. Design and Simulation extraction, injection, undulator, wakefield 2254
 
  • A. Vardanyan, G. Amatuni
    CANDLE, Yerevan
  The design and constructional features of the control system for 500 MHz and 3 GHz RF system of CANDLE linac are presented. The linac includes an electron gun that is modulated by 500 MHz generator to produce 1 ns electron bunches, 500 MHz and 3 GHz bunchers, pre-accelerating cavity and the main accelerating section at 3 GHz. An important feature of the presented control system is a high level synchronization of amplitude-phase characteristics of the sub-systems that provide the required energy-space characteristics of the accelerated beam. This puts strict requirements on RF frequency, amplitude and phase stabilization. A digital feedback system has been adopted to provide flexibility in the control algorithms. The main feature is a 9 MHz sampling rate for the cavity signals and digital I/Q detection. The design was performed using the RF analyze tool, based on MATLAB SIMULINK, which allows the simulation and analyzes of the field regulation quality. The simulation results for CANDLE Linac RF system, based on the output parameters of electron beam are given.  
 
THPKF004 The Australian Synchrotron Project - Update extraction, injection, undulator, wakefield 2257
 
  • A. Jackson
    ASP, Melbourne
  The Australian Synchrotron - a 3rd generation synchrotron light facility based on a 3-GeV electron storage ring - is under construction at a site adjacent to Monash University in the Metropolitan District of Melbourne. Site preparation started in September 2003 and project completion is scheduled for March 2007. In this paper we present an overview of the facility and discuss progress to date in meeting this very agressive schedule.  
 
THPKF005 The Australian Synchrotron Project Storage Ring and Injection System Overview extraction, injection, undulator, wakefield 2260
 
  • G. LeBlanc, M.J. Boland, Y.E. Tan
    ASP, Melbourne
  This paper describes the Australian Synchrotron storage ring. The storage ring is a 3 GeV machine with 14 cells and a circumference of 216 m. The unit cell is based on a Double Bend Achromat (DBA) structure. The design of the magnet lattice and the results of simulations pertaining to the storage ring performance are presented.  
 
THPKF006 Lifetime Studies in the LNLS Electron Storage Ring extraction, injection, undulator, wakefield 2263
 
  • N.P. Abreu, N.P. Abreu
    UNICAMP, Campinas, São Paulo
  • P.F. Tavares
    LNLS, Campinas
  In this paper we present a set of measurements performed at the 1.37 GeV electron storage ring of the Brazilian Synchrotron Light Source. We measured the beam lifetime as a function of: current per bunch, gap voltage and position of horizontal and vertical scrapers. Those measurements helped us to determine the contribution of various particle loss mechanisms (Touschek, elastic and inelastic scattering and quantum fluctuations) to the lifetime of the beam. Comparison with theory is also presented as well as an interpretation of each effect.  
 
THPKF007 Canadian Light Source Status and Commissioning Results extraction, undulator, wakefield, laser 2266
 
  • L. Dallin, R. Berg, J.C. Bergstrom, X. Shen, R.M. Silzer, J.M. Vogt, M.S. de Jong
    CLS, Saskatoon, Saskatchewan
  The storage ring for the Canadian Light Source (CLS) was completed in August 2003. By January 2004, after about shifts of commissioning beam currents of up to 25 mA with 0.7 hr lifetimes were achieved. Injection times for 25 mA are about 4 minutes. Commissioning activities include global orbit correction, measurement of machine parameters and beam-based diagnostices. Features of the CLS are a compact lattice (170 m) for a 2.9 GeV storage ring, high performance magnets and a superconducting RF cavity. By July, when beamlines become operational, currents up to 100 mA with 4 hour lifetimes are expected.  
 
THPKF030 Progress Report on the construction of SOLEIL booster, beamloading, damping, beamlosses 2332
 
  • J.-M. Filhol
    SOLEIL, Gif-sur-Yvette
  The construction of SOLEIL, the French new SR facility, was launched in Jan 2002. The construction of the building has started in Aug 2003 and will enable a progressive beneficial occupancy from summer 2004 onwards. It is foreseen to achieve the commissioning of the 100 MeV Linac by the end of 2004, of the 3 Hz Booster in spring 2005 and of the 2.75 GeV Storage Ring by the end of 2005. All the major components have been ordered and some have already been delivered : the Booster and SR dipole magnets, the Linac sections and the Booster RF cavity. Some innovative development have been initiated specifically for SOLEIL: A 352 MHz SC RF cavity, solid state RF amplifiers for the Booster (40 kW) and the Ring (2 x 190 kW), BPM digital electronics, Al NEG coated vacuum vessels for all straight parts of the ring, or electromagnetic undulators to provide high brilliance polarized light in the VUV range. In order to provide the best performances, significant attention was paid at each design stage (optics, magnets, BPM, vacuum and RF systems,..), involving a large effort of simulation, using 6D tracking codes, or evaluating in detail the contribution of each component to the machine impedance.

on behalf of the SOLEIL project team

 
 
THPKF031 High Power (35 KW and 190 KW) 352 MHZ Solid State Amplifiers for Synchrotron SOLEIL beamloading, damping, beamlosses, vacuum 2335
 
  • P. Marchand, R.L. Lopes, J. Polian, F. Ribeiro, T. Ruan
    SOLEIL, Gif-sur-Yvette
  In the SOLEIL Storage Ring (SR), two cryomodules, each containing a pair of superconducting cavities will provide the maximum power of 600 kW, required at the nominal energy of 2.75 GeV with the full beam current of 500 mA and all the insertion devices. Each of the four cavities will be powered with a 190 kW solid state amplifier consisting in a combination of 315 W elementary modules (about 750 modules per amplifier). The amplifier modules, based on a technology developed in house, with MOSFET transistor, integrated circulator and individual power supply, will be fabricated in the industry. In the booster, a 40 kW solid state amplifier (147 modules) will power a 5-cell copper cavity of the LEP type. The status and the test results of the different parts of the equipment are reported in this paper.  
 
THPKF032 Cleaning of Parastic Bunches in the ESRF Booster Synchrotron for Time Structure Modes of Operation booster, beamloading, damping, beamlosses 2338
 
  • E. Plouviez, N. Michel
    ESRF, Grenoble
  The ESRF injector booster accelerates electron bunches from 200 MeV to 6 GeV and inject them in a storage ring. It can accelerate a small number (1 to 5) of high charge bunches for the so called "time structure" filling mode operation of the SR. In this case we must avoid storing parasitic low charge bunches in the unused RF bucket of the SR. Until now this was achieved by a resonant knockout of these parasitic bunches on the beam stored in the SR. We have developed and implemented a system allowing the removal of these parasitic electrons during the acceleration in the booster, so that no extra cleaning is needed on the beam stored in the SR. This paper describes our setup and its key components, the tuning of the operating parameters of the system and presents the results achieved.  
 
THPKF033 Prospects for Long-term Lattice Upgrade at the ESRF booster, beamloading, damping, beamlosses 2341
 
  • A. Ropert, P. Elleaume, L. Farvacque, Y. Papaphilippou, T. Perron
    ESRF, Grenoble
  Twelve years after commissioning, the ESRF delivers routinely X-rays of brilliance, a factor hundred higher than the design target, to 45 beamlines. Further long-term improvements to the storage ring performance concern the reduction of the horizontal emittance leading to an increase of the brilliance and/or the increase of the number of beamlines from insertion device source points. In this paper, we review the different scenarios that can be envisaged with keeping untouched the existing tunnel and beamlines. Among them, the concept of the Double DBA structure that combines the reduction of emittance (a factor of 8) and the increase of the number of straight sections (64 instead of 32) looks the most attractive. Some of the challenging issues of such a scheme (squeezed space between magnets, innovative combined function magnets of unprecedented small aperture, small dynamic aperture) will be discussed.  
 
THPKF036 Developments of the FZP Beam Profile Monitor target, booster, beamloading, beamlosses 2350
 
  • N. Nakamura, M. Fujisawa, H. Kudo, H. Sakai, K. Shinoe, H. Takaki, T. Tanaka
    ISSP/SRL, Chiba
  • H. Hayano, T. Muto
    KEK, Ibaraki
  A beam profile monitor based on two Fresnel Zone Plates (FZPs) has been developed at the KEK-ATF damping ring. This monitor can perform real-time imaging of the electron beam with an X-ray imaging optics and the synchrotron radiation and measure the horizontal and vertical beam sizes with a high spatial resolution. A clear electron-beam image with the vertical beam size less than 10 microns was already obtained in the early measurements [*]. Thereafter some of the optical elements, the crystal monochromator, X-ray CCD camera and FZP holders, were improved and an X-ray pinhole mask was installed between the two FZPs for reducing the background of X-rays passing through the MZP (the second FZP). Aberrations due to alignment errors of the FZPs were studied with an analytical approach and a ray-tracing method and vibrations of the optical elements were measured in order to estimate their effects on the system performance. In this paper, we will present developments of the beam profile monitor with results of some beam-size measurements.

* K. Iida et al., Nucl. Instrum. Methods A506, p.41-49 (2003); N. Nakamura et al., Proc. of PAC2003, p.530-532

 
 
THPKF037 Quasi-isochronus Operation at NewSUBARU target, booster, beamloading, beamlosses 2353
 
  • Y. Shoji, S.H. Hisao, T. Matsubara
    LASTI, Ako-gun, Hyogo
  Quasi-isochronus operation is one of the operation modes of NewSUBARU, a 1.5 GeV VUV storage ring. NewSUBARU has six invert bending magnets to control the momentum compaction factor. The aim of this research is to explore the extreme reduction of electron bunch length by reducing the linear momentum compaction factor. We experimentally reduced the momentum compaction factor from 0.0014 down to less than 10-5, keeping the beam in the ring. The second-order momentum compaction factor was adjusted to almost zero, while keeping the third-order momentum compaction factor positive. The ring was operated at 1.0 GeV. Using a streak camera, the shortest bunch length we observed was 4 ps FWHM. With such a low momentum compaction factor, we expect an energy spreading by betatron oscillation even at the extremely low beam current.  
 
THPKF059 Adaption of an RF-gun from Thermionic to Photo Cathode target, gun, beamlosses, laser 2394
 
  • S. Werin, M. Berglund, M. Brandin, T. Hansen
    MAX-lab, Lund
  The current electron source for the injector at MAX-lab is a thermionic RF-gun. This gun produces a several ns long pulse with a significant beamloading. To allow for ?few bucket? operation and emittance reduction the gun will be adapted for operation with a ns laser system. The system to be installed during the spring 2004 is a 3 or 4th harmonic injection seeded Nd:YAG laser. The thermionic BaO cathode already in use will be used at a temperature just below thermal emission where a quantum efficiency of around 1* 10-4 is expected.  
 
THPKF075 LUX - A Recirculating Linac-based Facility for Ultrafast X-ray Science radiation, electron, coupling, simulation 2436
 
  • J.N. Corlett, W.A. Barletta, S. De Santis, L.R. Doolittle, W. Fawley, P.A. Heimann, S.R. Leone, D. Li, S.M. Lidia, G. Penn, A. Ratti, M. Reinsch, R.W. Schoenlein, J.W.  Staples, G.D. Stover, S.P. Virostek, W. Wan, R. Wells, R.B. Wilcox, A. Wolski, J.S. Wurtele, A. Zholents
    LBNL, Berkeley, California
  We present design concepts for LUX - a proposed source of ultra-fast synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux VUV-x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1 - 10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and to propagate electron beams carrying nm-scale density modulation in the final stages of cascaded harmonic generation. Synchronization of tens of femtoseconds is achieved by use of an optical master oscillator distributing timing signals over actively stabilized fiber, and generation of rf signals from the optical master oscillator. We describe technical developments in key areas including injection from a high repetition rate rf photocathode gun, lattice design, UV and soft x-ray production by high-gain harmonic generation, a kicker design for rapid transfer of the electron beam between radiator beamlines, lasers systems concepts, and synchronization between experimental pump lasers and the x-ray pulse.  
 
THPKF076 Plan to Upgrade the Advanced Light Source to Top-off Injection Operation radiation, electron, simulation, insertion 2439
 
  • D. Robin, B. J. Bailey, K.M. Baptiste, W. Barry, E. Byrne, J.-Y. Jung, S. Kwiatkowski, R.S. Mueller, H. Nishimura, S. Prestemon, S.L. Rossi, F. Sannibale, D. Schlueter, D. Shuman, C. Steier, G.D. Stover, T. Warwick
    LBNL, Berkeley, California
  • R.J. Donahue
    LBNL/ALS, Berkeley, California
  The brightness and thermal stability of the Advanced Light Source (ALS) is lifetime limited. Brightness improvements such as narrower gap insertion devices, smaller emittance coupling, and higher currents all result in short lifetimes. In addition current changes over a fill impact the thermal stability of both the storage ring and beamlines. In order to mitigate these limitations there is a plan to upgrade the injector of the ALS to full energy injection and to operate in a quasi-continuous filling (Top-Off) injection operation. With Top-Off, the ALS will increase its time-averaged current by two, reduce the vertical emmittance, and operate with smaller gap insertion devices. In this paper we describe our upgrade plan.  
 
THPKF077 A Fiber Optic Synchronization System for LUX radiation, laser, simulation, insertion 2442
 
  • R.B. Wilcox, L.R. Doolittle, J.W.  Staples
    LBNL, Berkeley, California
  The proposed LUX femtotsecond light source will support pump-probe experiments that will need to synchronize laser light pulses with electron-beam-generated X-ray pulses to less than 50fs at the experimenter endstations. To synchronize multiple endstation lasers with the X-ray pulse, we are developing a fiber-distributed optical timing network. A high stability clock signal from a modelocked laser is distributed via fiber to RF cavities (controlling X-ray probe pulse timing) and modelocked lasers at endstations (controlling pump pulse timing). The superconducting cavities are actively locked to the optical clock phase. Most of the RF timing error is contained within a 10kHz bandwidth, so these errors and any others affecting X-ray pulse timing (such as RF gun phase) can be detected and transmitted digitally to correct laser timing at the endstations. The lasers? timing jitter is limited to low frequency, and thus they will follow the controls (clock plus error correction) without adding much wideband error. Time delay through the fibers will be stabilized by comparing a retroreflected pulse from the experimenter endstation end with a reference pulse from the sending end, and actively controlling the fiber length. Numerical simulations and initial synchronization experimental results will be presented.  
 
THPKF078 Coherent Infrared Radiation from the ALS Generated via Femtosecond Laser Modulation of the Electron Beam electron, laser, simulation, insertion 2445
 
  • A. Zholents, J.M. Byrd, Z. Hao, M.C. Martin, D. Robin, F. Sannibale, R.W. Schoenlein, M. Venturini, M.S. Zolotorev
    LBNL, Berkeley, California
  Interaction of an electron beam with a femtosecond laser pulse co-propagating through a wiggler at the ALS produces significant modulation of the electron energies within a short ~100 fs slice of the electron bunch. Subsequent propagation of the energy-modulated bunch around the storage ring results in an appearance of a local temporal modulation of the electron density (micro-bunching) due to the dispersion of electron trajectories. The temporal width of this perturbation evolves as the electron bunch propagates around the ring. The shortest modulation, ~50 microns, appears in the ALS sector immediately following the wiggler magnet, and stretches to ~ 500 microns following propagation over 2/3 of a storage ring orbit. The modulated electron bunch emits single-cycle pulses of temporally and spatially coherent infrared light which are automatically synchronized to the laser pulses. The intensity and spectra of the infrared light were measured in two locations in the ring indicated above and were found to be in good agreement with analytical calculations. Ultra-short pulses of coherent infrared radiation are presently used for a fine tuning the laser ? electron beam interaction for generating femtosecond x-ray pulses.  
 
THPKF082 The Completion of SPEAR 3 electron, laser, simulation, insertion 2448
 
  • R.O. Hettel, R. Akre, S. Allison, P. Bellomo, R.F. Boyce, L. Cadapan, R. Cassel, B. Choi, W.J. Corbett, D. Dell'Orco, T. Elioff, I. Evans, R. Fuller, S. Hill, D. Keeley, N. Kurita, J. Langton, G. Leyh, C. Limborg-Deprey, D. Macnair, D.J. Martin, P.A. McIntosh, E. Medvedko, C.-K. Ng, I. Nzeadibe, J. Olsen, M. Ortega, G.C. Pappas, S. Park, T. Rabedeau, H. Rarback, A. Ringwall, P. Rodriguez, J.A. Safranek, H.D. Schwarz, B. Scott, J.J. Sebek, S. Smith, T. Straumann, J. Tanabe, A. Terebilo, T.A. Trautwein, C. Wermelskirchen, M. Widmeyer, R. Yotam, K. Zuo
    SLAC/SSRL, Menlo Park, California
  On December 15, 2003, 8 1/2 months after the last electrons circulated in the old SPEAR2 storage ring and 5 days after the beginning of commissioning, the first electrons were accumulated in the completely new SPEAR3 ring. The rapid installation and commissioning is a testimony to the SPEAR3 project staff and collaborators who have built an excellent machine and equipped it with powerful and accessible machine modeling and control programs. The final year of component fabrication, system implementation and testing, the 7-month installation period leading up to the beginning of commissioning, and lessons learned are described.  
 
THPKF084 Emerging Concepts, Technologies and Opportunities for Mezzo-scale Terahertz and Infrared Facilities electron, radiation, laser, simulation 2451
 
  • S. Chattopadhyay, S.T. Corneliussen, G.P. Williams
    Jefferson Lab, Newport News, Virginia
  Recent advances in particle beam, laser and radiofrequency technologies, combined with innovative concepts and techniques such as energy recovery, coherent synchrotron radiation-induced bunching, laser-particle beam scattering, ultrashort pulse slicing, cw high current and brightness phtoinjectors, ultrafast laser switching and compact engineered end products have opened up new opportunities and vistas in terahertz/infrared radiation sources not available before. Such sources would complement the high energy short wavelength x-ray sources in that they will allow us to probe collective processes and their ?function? in complex systems and materials, in a fashion complementary to probing structure via x-rays. We will outline and give examples of both the scientific reach of such radiation sources as well as examples of a few conceived facilities and techniques worldwide spanning a diversity of spectral, coherence, brightness and application ranges in the long wavelength. Such facilities fall in the category of mezzo-scale facilities, bracketed by table top lasers on one hand and large scale synchrotron radiation sources on the other and offer very unique and directed advances in a few key areas in life, materials, imaging, instrumentation and communication sciences.  
 
THPKF088 NSLS II: A Future Source for the NSLS radiation, laser, simulation, insertion 2454
 
  • J.B. Murphy, J. Bengtsson, L. Berman, R. Biscardi, A. Blednykh, G.L. Carr, W.R. Casey, S.B. Dierker, E. Haas, R. Heese, S. Hulbert, E. Johnson, C.C. Kao, S.L. Kramer, S. Krinsky, I.P. Pinayev, R. Pindak, S. Pjerov, B. Podobedov, G. Rakowsky, J. Rose, T.V. Shaftan, B. Sheehy, D.P. Siddons, J. Skaritka, N. Towne, J.-M. Wang, X.J. Wang, L.-H. Yu
    BNL/NSLS, Upton, Long Island, New York
  The National Synchrotron Light Source at BNL was the first dedicated light source facility and has now operated for more than 20 years. During this time, the user community has grown to more than 2400 users annually. To insure that this vibrant user community has access to the highest quality photon beams, the NSLS is pursuing the design of a new ultrahigh brightness (~ 1E21) electron storage ring, tailored to the 0.3-20 keV photon energy range. We present our preliminary design and review the critical accelerator physics design issues.  
 
THPLT003 Vibrating Wire Scanner Parameters Optimization radiation, laser, simulation, insertion 2457
 
  • S.G. Arutunian, K.G. Bakshetyan, N.M. Dobrovolski, M.R. Mailian, V.A. Oganessian, H.E. Soghoyan, I.E. Vasiniuk
    YerPhI, Yerevan
  • K. Wittenburg
    DESY, Hamburg
  The idea to use the metallic vibrating wire as a scanner of particles beams was experimentally confirmed [1, 2] and showed unprecedented sensibility and a huge dynamic rage of the output signal. In this work the response time of the system is estimated on the base of the dynamic model of heat transfer through the wire. A comparison of different materials of the wire is presented and the most suitable materials for different tasks are suggested. The dielectric materials are considered as possible materials of the wire, use of which allows to eliminate the electromagnetic induction from high current beams during the scanning of beam halo. The results of scanning of the iron ion beam of the mass spectrometer are presented. 1. Arutunian S.G., Avetisyan A.E., Dobrovolski N.M., Mailian M.R., Vasiniuk I.E, Wittenburg K., Reetz R., Problems of Installation of Vibrating Wire Scanners into Accelerator Vacuum Chamber. - Proc. 8-th Europ. Part. Accel. Conf. (3-7 June 2002, Paris, France), pp. 1837-1839. 2. Arutunian S.G., Dobrovolski N.M., Mailian M.R., Vasiniuk I.E., Vibrating wire scanner: first experimental results on the injector beam of Yerevan synchrotron.- Phys. Rev. Special Topics. - Accelerators and Beams, 2003, v. 6, 042801.  
 
THPLT004 Toroidal Cavity Loaded with an Electron Beam laser, simulation, insertion, target 2460
 
  • E.D. Gazazyan, T. Harutyunyan, D. Kalantaryan
    YSU, Yerevan
  • V. Kocharyan
    DESY, Hamburg
  Three problems have been considered in this paper: the development of Maxwell's equations strict solution method to define the electromagnetic own values and own functions of the toroidal cavity; the radiation of the charged bunch rotating along the average radius, and, at last, the consideration of the case of a toroid filled with dielectric medium. The peculiarities of this radiation have been investigated as well. We suppose to consider the case when toroid is filled with plasma like a disperse medium.  
 
THPLT005 Ultra-high Frequency Scanning Cavities for Non-relativistic Electron Beam laser, simulation, insertion, target 2463
 
  • G.G. Oksuzyan, E.D. Gazazyan, A.T. Margaryan, A.D. Ter-Poghosyan
    YerPhI, Yerevan
  • M. Ivanyan
    CANDLE, Yerevan
  The different scanning schemes based on the RF cavities for non-relativistic electron beam are examined. Optimization criteria for various types of cavities were developed. A complete picture of the beamscanning at a given point of interest is obtained.  
 
THPLT006 A Comparison of COSY DA Maps with Analytic Formulae for Orbit Functions of a Non-scaling FFAG Accelerator laser, simulation, insertion, target 2466
 
  • S.R. Koscielniak
    TRIUMF, Vancouver
  Fixed Field Alternating Gradient (FFAG) magnetic lattices with fixed, possibly high, radio-frequency proposed for muon acceleration have unusual requirements: relative momentum swing dp/p of ± 30% and relative spread of revolution frequencies < 10-3. It is not evident whether the existing accelerator optical design codes are sufficiently accurate for such a large momentum range. Analytic expressions for orbit displacements, tunes and path length have been derived for thick-element models of doublet, F0D0 and FDF triplet lattices; it is this paper's purpose to compare these with values computed by SYNCH and COSY, and truncated Taylor maps constructed by Lie algebra. The mutual agreement of results from independent sources will serve to validate them all. A mathematical necessity is that one at least of the magnets be of the combined-function type, and with entrance and exit faces disposed in a sector layout. It is sufficient to consider the triplet case because in the limit that the two F quadrupoles are combined, the cell reduces to the simpler F0D0. We use as our example a "nonscaling" FFAG ring proposed for accelerations of muons over the momentum range 10-20 GeV/c.  
 
THPLT007 New Beam Profile Monitor Based on GEM Detector for the AD Transfer and Experimental Lines antiproton, laser, simulation, insertion 2469
 
  • J. Bosser, K. Gnanvo, J. Spanggaard, G. Tranquille
    CERN, Geneva
  Many multi-wire proportional chambers, (MWPC's), are installed on the CERN Antiproton Decelerator (AD) transfer and experimental lines. They are used for the steering and profile measurement of the low energy antiproton beam that is extracted at the energy of 5.3 MeV from the AD machine. At this very low energy, the standard MWPC's are not only destructive for the beam but also perturb strongly the 2D profile measurement. These chambers are also based on technology that is outdated and in recent years have shown to be fragile and expensive to repair. For these reasons a new, low cost profile monitor, based on a Gas Electron Multiplier (GEM) detector is under development as a possible replacement of the MWPC's. This new profile monitor will enable high precision, true 2D profile measurements of the low energy antiproton beam. In this paper, we present the modification of the standard GEM detector required by our specific application and the first results of the profile monitor with antiproton beams.  
 
THPLT008 A Beam Condition Monitor for the Experimental Areas of the LHC antiproton, laser, simulation, insertion 2472
 
  • L. Fernandez-Hernando, L. Fernandez-Hernando, C. Ilgner, A. Oh, H. Pernegger
    CERN, Geneva
  • A. Macpherson
    PSI, Villigen
  • T. Pritchard
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • R. Stone
    Rutgers University, The State University of New Jersey, Piscataway, New Jersey
  The CERN Large Hadron Collider (LHC) will store 2808 bunches per colliding beam, with each bunch consisting of 1·1011 protons at an energy of 7 TeV. If there is a failure in an element of the accelerator, the resulting beam losses could cause damage not only to the machine but also to the experiments. A Beam Condition Monitor (BCM) is foreseen to monitor fast increments of fluence rate near the interaction point and, if necessary, to generate an abort signal to the LHC accelerator control to dump the beams. The system is being developed initially for the CMS experiment, but is sufficiently general to find potential applications elsewhere. Due to its high radiation hardness, CVD diamond was chosen for investigation as the BCM sensor. Various samples of CVD diamond have been characterised extensively with both a Sr-90 source and in a high intensity testbeam in order to assess the capabilities of such sensors and to study whether this detector technology is suitable for a BCM system. A selection of results from these investigations is presented.  
 
THPLT009 Comparative Transverse Distribution Measurements between the New SPS Rest Gas Ionisation Monitor and the Wire Scanner Monitors. antiproton, laser, simulation, insertion 2475
 
  • C. Fischer, B. Dehning, J. Koopman, D. Kramer, F. Roncarolo
    CERN, Geneva
  During the past two years, a new Ionization Profile Monitor was installed and tested in the CERN SPS. In parallel modifications were made on various wire scanner monitors. The aim is to develop instruments performing reliable measurements of transverse beam distributions in the SPS and in the LHC, in order to control the stringent emittance preservation requirements. Measurements made with the two types of monitors were performed under various conditions of LHC type beams, ranging from a pilot bunch up to beams having in the SPS nominal distributions in bunch number, intensity and energy for injection into the LHC. The data provided by the two types of instruments are compared. In the case of discrepancies, an analysis of the possible reasons is made. The cures implemented and the improvements foreseen are discussed.  
 
THPLT062 Alternating-phase-focused Linac for an Injector of Medical Synchrotrons vacuum, antiproton, gun, emittance 2628
 
  • Y. Iwata, T. Fujisawa, T. Furukawa, T. Kanai, M. Kanazawa, N. Kanematsu, M. Komori, S. Minohara, T. Murakami, M. Muramatsu, K. Noda, M. Torikoshi, S. Yamada
    NIRS, Chiba-shi
  • Y.F. Fujii, T. Mitsumoto, H. Tsutsui
    SHI, Tokyo
  • T. Fujimoto, H.O. Ogawa, S. Shibuya
    AEC, Chiba
  • V. Kapin
    MEPhI, Moscow
  Tumor therapy using Heavy Ion Medical Accelerator in Chiba (HIMAC) has been made over ten years at National Institute of Radiological Sciences (NIRS). Due to the successful clinical results, the project on developing compact medical accelerators for the tumor therapy has been started. To design these compact facilities, the size of a linac as well as the construction and operation costs is important. To satisfy these requirements, we propose Alternating-Phase-Focused (APF) linac using an Interdigital H-mode cavity. Since the axial and radial focusing of beam is made just with the acceleration rf field, no additional focusing elements is needed for the APF linac. This feature would make the costs lower than those of conventional linacs. The practical design of the APF linac will be presented.