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Paper Title Other Keywords Page
MOPKF009 Photoinjector Studies for the BESSY Soft X-ray FEL linac, 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.  
 
MOPKF010 The Output Performance of the BESSY Multi-stage HGHG-FEL alignment, damping, brilliance, photon 318
 
  • A. Meseck, M. Abo-Bakr, B.C. Kuske
    BESSY GmbH, Berlin
  The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generatio(HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral range(0.02 keV - 1. keV). A photoinjector and a superconducting 2.3GeV CW linac will feed three independent HGHG-FEL-lines. As the efficiency of the interaction between the radiation and the electron beam is higher in a helical undulator, one would tend to prefer such a device for the HGHG scheme. Also a higher K-value of the modulators seems to be advantageous. This is not necessarily the case. We present simulation studies for the BESSY-HGHG-FELs and discuss the output performance for ‘‘helical stages'' and increased K value of the modulators.  
 
MOPKF011 Output Variability of the BESSY Soft X-ray FEL alignment, damping, brilliance, photon 321
 
  • A. Meseck, M. Abo-Bakr, B.C. Kuske
    BESSY GmbH, Berlin
  The BESSY soft X-ray FEL is planned as a High Gain Harmonic Generation HGHG) FEL multi-user facility covering the VUV to soft X-ray spectral rang(0.02 keV - 1 keV). A photoinjector and a superconducting $2.3\,GeV$ CW linac will feed three independent HGHG-FEL-lines. Depending on the optimisation criteria, it is possible to obtain either maximum output power or pure spectrum from the same HGHG-line. We present simulation studies for the BESSY-HGHG-FELs and discuss the possible variability of the output performance.  
 
MOPKF012 A 7T Multipole Wiggler in BESSY II: Implementation and Commissioning Results wiggler, radiation, damping, alignment 324
 
  • E. Weihreter, J. Feikes, P. Kuske, R. Müller, G. Wustefeld
    BESSY GmbH, Berlin
  • D. Berger
    HMI, Berlin
  • N.A. Mezentsev, V. Shkaruba
    BINP SB RAS, Novosibirsk
  To generate hard X-ray beams for residual stress analysis and for magnetic scattering with the BESSY II SR source, a 7T wiggler with 17 poles has been implemented. Several problems had to be solved. Wake fields induced by smaller steps in the geometry of the radiation shield inside the beam chamber led to intolerable LHe consumption, which have been analysed numerically and then cured by improving the shield geometry. Much of the routine operation procedures are influenced by the unusually high radiation power level of max. 55 kW. For system protection an interlock system dumps the electron beam automatically in case of relevant error events. This wiggler is by far the strongest perturbation of the linear beam optics, breaking seriously the symmetry of the ring. Beam optical parameters including tune shift and beta beat have been measured to quantify these perturbations and develop efficient cures to limit the negative effects on beam lifetime and dynamic aperture. So far the wiggler is operated at 2.8 T and max. currents up to 250 mA in normal user shifts.  
 
MOPKF013 The Influence of the Main Coupler Field on the Transverse Emittance of a Superconducting RF Gun wiggler, radiation, damping, alignment 327
 
  • D. Janssen
    FZR, Dresden
  • M. Dohlus
    DESY, Hamburg
  For the Rossendorf superconducting RF gun project the influence of the additional RF field, created in the cavity by the RF power flow at the main coupler, is discussed. One end of the gun cavity is occupied by the cathode insert, so all flanges are concentrated on the other end. In the "flange plane" of the cavity two HOM coupler, the pic up and the main coupler are located. If we normalize the RF field in the cavity by the condition Eacc = 25MV/m and assume a beam power of 10kW (CW mode), we obtain an quality factor Qext = 2.2*10**7. A three dimensional field calculation using the MAFIA code, gives the field perturbation near the main coupler. Tracking calculation with ASTRA show,that this perturbation increases the transversel emittance between 1 and 4%, nearly independent from the bunch charge. This result shows, that for average beam powers in the vicinity of 10kW effects, connected with the assymetric input of RF power can be neglected.  
 
MOPKF014 Emittance Compensation of a Superconducting RF Photoelectron Gun by a Magnetic RF Field wiggler, radiation, damping, alignment 330
 
  • D. Janssen
    FZR, Dresden
  • V. Volkov
    BINP SB RAS, Novosibirsk
  For compensation of transverse emittance in normal conducting RF photoelectron guns a static magnetic field is applied. In superconducting RF guns the application of a static magnetic field is impossible. Therefore we put instead of a static field a magnetic RF field (TE - mode) together with the corresponding accelerating mode into the superconducting cavity of the RF gun. For a 3 _ cell cavity of the superconducting gun with frequencies f = 1.3GHz for the accelerating mode and f = 3.9 GHz for the magnetic mode and a bunch charge of 1 nC a transversal emittance of 0.5 mm mrad has been obtained. In this case the maximal field strength on the axis were Ez = 50 MV/m for the accelerating mode and Bz = 0.34 T for the magnetic mode.(This corresponds to Bs(max) = 0.22T on the surface of the cavity). Possibilities for the technical realization (input of RF power for the TE mode, tuning of two frequencies in one cavity, phase stability) are discussed.  
 
MOPKF015 A Superconducting Photo-Injector with 3+1/2- Cell Cavity for the ELBE Linac wiggler, radiation, damping, alignment 333
 
  • J. Teichert, H. Buettig, P. Evtushenko, D. Janssen, U. Lehnert, P. Michel, Ch. Schneider
    FZR, Dresden
  • W.-D. Lehmann
    IfE, Dresden
  • J. Stephan
    IKST, Drsden
  • V. Volkov
    BINP SB RAS, Novosibirsk
  • I. Will
    MBI, Berlin
  After successful tests of an SRF gun with a superconducting half-cell cavity [*], a new SRF photo-injector for CW operation at the ELBE linac has been designed. In this report the design layout of the SRF photo-injector, the parameters of the superconducting cavity and the expected electron beam parameters are presented. The SRF gun has a 31/2-cell niobium cavity working at 1.3 MHz and will be operated at 2 K. The three full cells have TESLA-like shapes. In the half-cell the photocathode is situated which will be cooled by liquid nitrogen.

* D. Janssen et. al., First operation of a superconducting RF-gun, Nucl. Instr. and Meth. A507(2003)314

 
 
MOPKF016 S2E Simulations on Jitter for European XFEL Project wiggler, radiation, damping, alignment 336
 
  • Y. Kim, Y. Kim, D. Son
    CHEP, Daegu
  • K. Floettmann, T. Limberg
    DESY, Hamburg
  In order to generate stable 0.1 nm wavelength SASE source at the European X-ray laser project XFEL, we should supply high quality electron beams with constant beam characteristics to a 200 m long undulator. Generally, beam parameters such as peak current and energy spread are significantly dependent on jitter or error in RF phase and RF amplitude of superconducting accelerating modules, and magnetic field error of bunch compressors. In this paper, we describe the start-to-end simulations from the cathode to the end of linac to determine the jitter and error tolerances for the European XFEL project.  
 
MOPKF017 New Simulations on Microbunching Instability at TTF2 wiggler, damping, alignment, emittance 339
 
  • Y. Kim, Y. Kim, D. Son
    CHEP, Daegu
  • K. Floettmann
    DESY, Hamburg
  Microbunching instability in the FEL driver linac can be induced by collective self-fields such as longitudinal space charge, coherent synchrotron radiation, and geometric wakefields. In this paper, we describe the first start-to-end simulations including all important collective self-fields from the cathode to the end of TTF2 linac with 1.5 million macroparticles.  
 
MOPKF018 Injector and Bunch Compressor for the European XFEL Project wiggler, damping, alignment, linac 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.  
 
MOPKF020 Proposal for a Sub-100 fs Electron Bunch Arrival-time Monitor for the VUV-FEL at DESY laser, wiggler, electron, damping 345
 
  • H. Schlarb, S. Düsterer, J. Feldhaus, J. Hauschildt, R. Ischebeck, K. Ludwig, B. Schmidt, P. Schmüser, S. Simrock, B. Steffen, F. Van den Berghe, A. Winter
    DESY, Hamburg
  • P.H. Bucksbaum, A. Cavalieri, D. Fritz, S. Lee, D. Reis
    Michigan University, Ann Arbor, Michigan
  For pump-probe experiments at the VUV-Free Electron Laser at DESY, an external optical laser system will be installed, capable of delivering ultra-short pulses of high intensity. The laser pulses with a center wavelength of 800 nm are synchronized with the VUV-FEL beam which covers the wavelength range between 6 nm and 80 nm. The expected pulse durations are typically 100 fs FWHM or below. For high-resolution pump-probe experiments a precise knowledge of the time difference between both pulses is mandatory. In this paper we describe the layout and the design of a high-precision electron bunch arrival time monitor based on an electro-optic technique. We present the numerical results of simulations that include: the laser propagation in a specifically designed demanding optical system, the laser transport through a 150 m long optical fibre, the electro-optically induced effect in different types of crystals and for different electron bunch shapes as well as the effects of wake fields on the co-propagating electric-fields and their impact on the observable signals.  
 
MOPKF026 Conditioning and High Power Test of the RF Guns at PITZ laser, wiggler, damping, alignment 357
 
  • J.H. Han, K. Abrahamyan, J. Bähr, H.-J. Grabosch, M. Krasilnikov, D. Lipka, V. Miltchev, A. Oppelt, B. Petrosyan, D. Pose, L. Staykov, F. Stephan
    DESY Zeuthen, Zeuthen
  • I. Bohnet, J.-P. Carneiro, K. Floettmann, S. Schreiber
    DESY, Hamburg
  • M.V. Hartrott, R. Richter
    BESSY GmbH, Berlin
  • P. Michelato, L. Monaco, D. Sertore
    INFN/LASA, Segrate (MI)
  This paper describes the recent results of conditioning and high power tests of the photocathode RF guns at the Photo Injector Test Facility at DESY Zeuthen (PITZ). For successful operation of high gain SASE FELs, high phase space density of the electron beam is required. A high gradient in the gun has to be applied to improve the quality of the space charge dominated beams. In addition, long RF pulses and high repetition rate should be achieved to provide a high average power of FEL radiation. The first PITZ RF gun has been successfully tested at a mean power of 27 kW (900μseconds, 10 Hz, and 3 MW) and has been installed at the VUV-FEL at DESY Hamburg. Another RF gun has been installed at PITZ in January 2004 and is being conditioned for high power tests. The dark current behavior for various cathodes and for all operating schemes is also presented.  
 
MOPKF046 Photoelectron RF Gun Designed as a Single Cell Cavity injection, emittance, booster, cathode 411
 
  • H. Dewa, T. Asaka, H. Hanaki, T. Kobayashi, A. Mizuno, S. Suzuki, T. Taniuchi, H. Tomizawa, K. Yanagida
    JASRI/SPring-8, Hyogo
  • J. Sasabe
    Hamamatsu Photonics K.K., Hamakita, Shizuoka
  • M. Uesaka
    UTNL, Ibaraki
  The paper describes the recent improvements of S-band RF-gun at SPring-8. The cavity of the gun is a single-cell pillbox, and the copper inner wall is used as a cathode. The electron beam from the cathode was accelerated up to 4.1 MeV at an electric field of 175 MV/m. For emittance compensation, two solenoid magnets were used. A 3m linac and a quadrupole scan emittance diagnostic were added after the RF-gun. The beam energy spread and beam emittance after the linac is presented. The beam emittance measured with quadrupole scan is compered to that measured with double slits just after the RF-gun. For high quantum efficiency, Cs2Te cathode was also tested. It is vacuum sealed in a cartridge-type electric tube and four tubes can be installed in a vacuum chamber behind the cavity. Although the quantum efficiency after RF conditioning for two hours to achieve 90MV/m was 3%, it decreased to 1% after the 28 hours RF conditioning.  
 
MOPKF047 Suppression of Stored Beam Oscillation Excited by Beam Injection emittance, booster, cathode, vacuum 414
 
  • T. Ohshima, N. Kumagai, M. Masaki, S. Matsui, H. Ohkuma, K. Soutome, M. Takao, H. Tanaka
    JASRI/SPring-8, Hyogo
  Top-up operation is scheduled from May 2004 at SPring-8. For this operation it is important that frequent beam injections should not excite the oscillation of stored beams. However, injection bump orbit was not closed perfectly and residual beam oscillations lead to increase of effective beam sizes by twice and three times in the horizontal and vertical direction respectively. We are trying to reduce these excited oscillations to less than one third of the usual beam sizes. For the suppression of horizontal one, we applied a novel scheme to reduce the effect due to the nonlinearity of sextupole magnets by adjusting the strength ratio of the sextupoles. The field similarity of bump magnets was also improved by replacing them with newly designed ones, where the effect of eddy current at the end plates was reduced. These countermeasures suppressed the horizontal oscillation by about one order. For the suppression of vertical one, the excitation mechanism has being investigated in detail. Presently the tilt angle adjustment of bump magnets reduced the vertical oscillation by one third. For further reduction of these oscillations, corrections with pulse-magnets is under investigation.  
 
MOPKF048 Injection Beam Loss at the SPring-8 Storage Ring injection, emittance, booster, cathode 417
 
  • M. Takao, T. Ohshima, S. Sasaki, J. Schimizu, K. Soutome, H. Tanaka
    JASRI/SPring-8, Hyogo
  Capture efficiency of injection beam is extremely important for top-up operation because open photon shutter permits the bremsstrahlung from lost particles to be transported to experimental floor. Furthermore, since the SPring-8 storage ring has many in-vacuum insertion devices with narrow gap, the demagnetization by the lost electron bombardment is also serious to the beam injection with gap closing. To clarify the loss mechanism of injected beam at the SPring-8 storage ring, we investigate the loss process under various conditions of the storage ring, and especially measure the dependence of injection loss rate on gaps of insertion devices. Comparing the measurements with simulations, we found that an injected particle with a large horizontal amplitude begins to oscillate in vertical direction through error magnetic field and eventually disappears at the vertical limit. It is also found that the low chromaticity of the storage ring is effective for the reduction of injection beam loss. In this paper, we report the loss mechanism of the injection beam of the SPring-8 storage ring and the possible improvements of the capture efficiency.  
 
MOPKF056 Injector Design for the 4GLS Energy Recovery Linac Prototype injection, wiggler, bunching, cathode 437
 
  • C. Gerth, F.E. Hannon
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Daresbury Laboratory has been given funding for the construction of an Energy Recovery Linac Prototype (ERLP) that operates at a target electron beam energy of 35 MeV and drives an IR oscillator FEL. The ERLP serves as a test-bed for the study of beam dynamics and accelerator technology important for the design and construction of the proposed 4th Generation Light Source (4GLS). A key component of the ERLP is a high-brightness injector. The injector consists of a DC photocathode gun, which is currently being built at Daresbury Laboratory and based on the design of the gun for the IR demonstrator FEL at Thomas Jefferson National Accelerator Facility. The gun section is followed by a conventional buncher cavity, a super-conducting booster and a transfer line to the main linac. In this paper, the design of the ERLP injector is discussed. The performance of the injector has been studied using the particle tracking code ASTRA.  
 
MOPKF058 Construction of an APPLE-II Type Undulator at Daresbury Laboratory for the SRS injection, wiggler, bunching, cathode 440
 
  • F.E. Hannon, J.A. Clarke, C. Hill, A.A. Muir, D.J. Scott, B.J.A. Shepherd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  A new variable polarisation undulator of the APPLE-II type has been designed and constructed at Daresbury Laboratory. Testing of the 56mm period device has recently started in the new Magnet Test Facility at Daresbury Laboratory. This paper presents the magnetic and mechanical design of the undulator, and the first magnetic measurement results.  
 
MOPKF059 Magnet Specification for the Daresbury Laboratory Energy Recovery Linac Prototype wiggler, bunching, cathode, insertion 443
 
  • N. Thompson, N. Marks
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Daresbury Laboratory has funding for the design and construction of an Energy Recovery Linac (ERL) prototype to facilitate the R&D necessary for the 4th Generation Light Source (4GLS). In the prototype a 35MeV electron beam will be used to drive an Infra-Red Oscillator Free-Electron Laser. The ring consists of two 180°; triple bend achromats, two straight sections, an injection chicane, an extraction chicane and two bunch compression/decompression chicanes. A number of pre-existing magnets will be used in the ring so the new magnets have been designed to ensure compatibility with the existing designs, enabling common power supply, vacuum and control system specifications. This paper gives an overview of the magnet requirements for the facility and details of the engineering realisation.  
 
MOPKF060 Space Charge Effects for the ERL Prototype at Daresbury Laboratory wiggler, bunching, cathode, insertion 446
 
  • B.D. Muratori, C. Gerth
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • N. Vinokurov
    BINP SB RAS, Novosibirsk
  Daresbury Laboratory is currently building an Energy Recovery Linac Prototype (ERLP) that will operate at a beam energy of 35 MeV. In this paper we examine the Space Charge effects on the beam dynamics in the ERLP injector line. This is done in two distinct ways. The first is based on an analytic formula derived by Vinokurov through the envelope equations and a Kapchinsky-Vladimirsky (KV) distribution. This formula gives a rough estimate of the space charge effects in the case that no quadrupoles or dipoles are present in the injector line. The second estimate is given by the multi-particle tracking code ASTRA for the whole injector line both with and without quadrupoles. Both methods are compared and are found to be in good agreement. Typical examples of injector lines are given together with specific calculations for the ERLP.  
 
MOPKF061 Optics Layout for the ERL Prototype at Daresbury Laboratory wiggler, bunching, cathode, insertion 449
 
  • B.D. Muratori, H.L. Owen, J.A. Varley
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The overall optics for the Energy Recovery Linac Prototype (ERLP) at Daresbury Laboratory is summarised. This includes the layout of the injector line, all chicanes used, as well as details of both the outward and return TBA arcs. The tunability in several sections of the machine is examined under different operational modes and starting parameters from the end of the booster to the dump.  
 
MOPKF062 Choice of Arc Design for the ERL Prototype at Daresbury Laboratory wiggler, bunching, cathode, insertion 452
 
  • H.L. Owen, B.D. Muratori
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The choice of arc design for the Energy Recovery Linac Prototype (ERLP) to be built at Daresbury Laboratory is investigated. Both the overall merits and disadvantages of a TBA arc and Bates bend are considered, and space restrictions particular to Daresbury Laboratory given. Some magnet parameters are given together with a summary of the layout of the ERLP.  
 
MOPKF063 4GLS and the Prototype Energy Recovery Linac Project at Daresbury wiggler, bunching, cathode, insertion 455
 
  • M.W. Poole, E.A. Seddon
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  The 4GLS project is a novel next generation solution for a UK national light source proposed to be sited at Daresbury. It is based on an energy recovery linac (ERL) operating at high average beam currents up to 100mA and with compression schemes producing pulses in the 10-100 fs range. This would provide a unique spontaneous emission source with high average brightness output both from undulators and bending magnets. In addition to this operating regime a high peak current mode would also be possible at lower duty cycle, enabling a high gain FEL amplifier to generate XUV radiation. Longer wavelength FELs are also planned. This challenging accelerator technology, new to Europe, necessitates a significant R&D programme and as a major part of this a low energy prototype, the ERLP, is being constructed at Daresbury. The paper summarises the ERLP design specification, describes the component solutions adopted and explains the 4GLS project status and plans.  
 
MOPKF064 Design Considerations for a Helical Undulator for the Production of Polarised Positrons for TESLA wiggler, bunching, cathode, insertion 458
 
  • D.J. Scott, S.C. Appleton, J.A. Clarke, B. Todd
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • E. Baynham, T.W. Bradshaw, S.C. Carr, Y. Ivanyushenkov, J. Rochford
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  An efficient and simple method for the production of positrons, in the necessary quantities, is one of the problems facing proposals for any future e+ e- Linear Collider project. The possibility of colliding polarised beams would also be an advantage. One method to produce a polarised positron beam uses circularly polarised radiation generated by the main electron beam passing through a helical undulator. Design considerations and calculations for two undulators, based on super-conducting and pure permanent magnet technologies, for the TESLA machine, are presented.  
 
MOPKF065 Magnet Block Sorting for Variably Polarising Undulators wiggler, bunching, cathode, insertion 461
 
  • D.J. Scott
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  Effective sorting of permanent magnet blocks for undulators can reduce the adverse effects of magnetic in-homogeneities and engineering tolerances on the electron beam. For variably polarising undulators the number of different modes of operation make defining the objective function of a particular permutation more difficult than for a planar device. Factors required in defining a good objective function for a new APPLE-II type helical undulator for the SRS are discussed. These factors include calculating the magnetic field integrals, the particle trajectory and rms optical phase error. The effects of different weighting of these functions in the objective function are also discussed. A comparison of different optimisation techniques, including simulated annealing and Monte Carlo methods is also made.  
 
MOPKF066 Magnetic Design of a Focusing Undulator for ALPHA-X undulator, wiggler, bunching, cathode 464
 
  • B.J.A. Shepherd, J.A. Clarke
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  ALPHA-X is a four-year project shared between several research groups in the UK to build a laser-plasma accelerator and produce coherent short-wavelength radiation in an FEL. The FEL undulator will be a 1.5m long, 100 period permanent magnet device with a minimum gap of 3.5mm and a peak field of 0.7T. To focus the beam inside the undulator, several schemes were examined. In the scheme that was selected, the magnet blocks are designed so that the pole face is an approximation of a parabola. This focuses the beam horizontally and vertically. The magnetic design of the undulator is complete; design of the support structure is well under way. Test pieces have been built to ensure that the clamping arrangement is strong enough to cope with the magnetic forces involved. The complete undulator will be built in late 2004 at Daresbury Laboratory, and tested on-site in the new magnet test facility.  
 
MOPKF067 Comparison of Different Buncher Cavity Designs for the 4GLS ERLP undulator, wiggler, bunching, cathode 467
 
  • E. Wooldridge, C.D. Beard, C. Gerth
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • A. Buechner
    FZR/FWFE, Dresden
  A DC photocathode gun is part of the injector of the Energy Recovery Linac Prototype (ERLP) currently built at Daresbury Laboratory. A buncher is required for the ERLP to decrease the bunch length off the gun. Three different single-cell cavity designs were investigated: The Cornell buncher, the Elbe Buncher and an EU cavity without Higher Order Mode (HOM) dampers. The properties of these cavities were studied with the computer codes CST's Microwave Studio and ASTRA. The fundamental frequency and field pattern was investigated in Microwave Studio. The EU cavity had to be scaled from 500MHz as the required frequency for the buncher is 1.3GHz. As the anticipated kinetic energy of the electron beam after the gun is about 350keV a particle tracking code including the space charge forces is mandatory to study the effect of the different buncher cavity designs on the beam dynamics. The particle tracking code ASTRA was used to study the performance of the bunchers for a variety of beam parameters. From these investigations it was found that the three bunchers produce very similar effects on the particle bunch.  
 
MOPKF068 Experimental Study of the Stability Margin with Beam Heating in a Short-Period Superconducting Undulator for the APS undulator, wiggler, bunching, cathode 470
 
  • S.H. Kim, C. Doose, R. Kustom, E.R. Moog, K.M. Thompson
    ANL/APS, Argonne, Illinois
  A superconducting undulator with a period of 15 mm is under development at the Advanced Photon Source (APS). The undulator is designed to achieve a peak field on the beam axis of 0.8 T with an 8 mm pole tip gap and an NbTi coilpack current density of 1 kA/mm2. Because of the high current density in the coilpack, the superconducting magnet operates at about 75% of the short sample limit at 4.2K. Additional heat load to the coilpack, mainly due to the image currents and synchrotron radiation from the electron beam in the storage ring, will reduce the stability margin. An experiment was conducted to measure the reduction in the stability margin of the coilpack due to heat load on the beam chamber. The heat load was deposited in a 12-period prototype undulator using thin-film heaters attached to the inner surface of a simulated vacuum chamber. Evaluation of the stability margin based on the experiment and calculations of the beam heating and thermal conduction between the undulator and beam chamber will be discussed.  
 
MOPKF069 Engineering Design of the LUX Photoinjector undulator, wiggler, bunching, cathode 473
 
  • J.W.  Staples, S.P. Virostek
    LBNL, Berkeley, California
  • S.M. Lidia
    LBNL/AFR, Berkeley, California
  The photoinjector for the LBNL LUX project, a femtosecond-regime X-ray source, is a room-temperature 1.3 GHz 4-cell structure producing a 10 MeV, nominal 30 psec, 1 nanocoulomb electron bunch at a 10 kHz rate. The first cell is of reentrant geometry, with a peak field of 64 MV/m at the photocathode surface, the geometry of which will be optimized for minimum beam emittance. The high repetition rate and high peak power results in a high average surface power density. The design of the cavity, its cooling structure and power couplers, is coordinated with the configuration of the RF system, including a short, high-power driving pulse and active removal of stored energy after the beam pulse to reduce the average power dissipated in the cavity. An RF and thermal analysis will be presented, along with plans for a high average and peak power test of the first cell.  
 
MOPKF079 The Linac Coherent Light Source Photo-Injector Overview and Some Design Details linac, wiggler, cathode, 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 linac, wiggler, cathode, 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 linac, wiggler, cathode, 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 linac, wiggler, cathode, 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.  
 
MOPKF083 Inverse Free Electron Laser Heater for the LCLS laser, wiggler, electron, undulator 512
 
  • R. Carr, L.D. Bentson, P. Bolton, D. Dowell, P. Emma, A. Gilevich, Z. Huang, J.J. Welch, J. Wu
    SLAC, Menlo Park, California
  The LCLS Free Electron Laser employs an RF photocathode gun that yields a 1 nC charge bunch a few picoseconds long, which must be further compressed to yield the high current required for SASE gain. The very cold electron beam from the RF photocathode gun is quite sensitive to microbunching instabilities such as coherent synchrotron radiation (CSR) in the compressor chicanes and longitudinal space charge (LSC) in the linac. These effects can be Landau damped by adding energy spread to the electron bunch prior to compression. We propose to do this by interacting an infrared laser beam with the electron bunch in an undulator added to the LCLS gun-to-linac injector. The undulator is placed in a 4-bend chicane to allow the IR laser beam to propagate co-linearly with the e-beam while it oscillates in the undulator. The IR laser beam is derived from the photocathode gun laser. Simulations presented elsewhere in these proceedings show that the laser interaction damps the microbunching instabilities to a very great extent. This paper is a description of the implementation of the laser heater  
 
MOPKF084 Beam Instabilities in Lepton Ring of eRHIC laser, lepton, wiggler, undulator 515
 
  • D. Wang, M. Farkhondeh, C. Tschalaer, J. Van der Laan, F. Wang, A. Zolfaghari, T. Zwart
    MIT/BLAC, Middleton, Massachusetts
  • M. Blaskiewicz, Y. Luo, L. Wang
    BNL, Upton, Long Island, New York
  The eRHIC is a high luminosity lepton-hadron collider planned to be built in Brookhaven National Lab, Upton, New York, USA. The lepton machine of eRHIC is a completely newly designed machine complex to provide highly polarized lepton beams at up to 10 GeV energy for the high luminosity lepton-hadron collisions. This paper decribes major issues of collective effects in this lepton storage ring. Besides conventional impedance-driven instabilities, the electron cloud effects in positron operation and fast beam-ion effects in electron operation are of major conserns. The analytical and numerical estimats for major collective effects are made with different machine operation conditions.  
 
MOPLT101 Performances of the Beam Generated by Metal-Dielectric Cathodes in RF Electron Guns wiggler, electron, wakefield, beamloading 767
 
  • I.V. Khodak, I.V. Khodak, V.A. Kushnir
    NSC/KIPT, Kharkov
  The paper describes results of the experimental research of the metal-dielectric cathode operation in RF electron gun. Application of these cathodes permits RF guns to generate intense beams with nanosecond current pulse duration. Electron beam is extracted from plasma sheath developed during the surface vacuum flashover dielectric. Simulated and experimental parameters of the beam obtained at the single-cavity RF gun output are summarized in the paper. The beam formation and its interaction with microwave field of high strength are analyzed qualitatively. Results are compared with experimental results obtained before in the 1.5-cavity RF electron gun. First experimental results on electron beam generation by the RF gun with a ferroelectric cathode are discussed in the paper.  
 
MOPLT102 To the Problem of Wake-field Excitation for Advanced Accelerator Concept wiggler, electron, wakefield, beamloading 770
 
  • I.N. Onishchenko, V. Kiselev, A. Linnik, N. Onishchenko, G. Sotnikov
    NSC/KIPT, Kharkov
  • V. Ushkov
    RRC Kurchatov Institute, Moscow
  The advanced accelerator concept to use the wake-fields exited in dielectric by a sequence of electron bunches for high-gradient particle acceleration has been proposed and investigated in [*-***]. Two essential merits are being exploited. First of them [**] is the excitation by a regular sequence of electron bunches that allows superposing coherently the wake-fields excited by each bunch. The second one [***] concludes to multi-mode operation that leads to peaking of the resulting HF-field that is represented by a sequence of spikes of alternative signs with essentially higher amplitude comparatively to only principle mode excitation. The recent works performed in NSC/KIPT on theoretical studies, simulation, and experimental investigations of the wake-fields excitation by a train of 2 MeV electron bunches in a dielectric waveguide are presented. Transition and Cerenkov radiation excited by short bunches in a limited dielectric medium was theoretically investigated. The measurements of wake-fields output power and the electron energy spectrum were experimentally performed.

* W.Gai, P.Schoessow, B.Cole et al. Phys. Rev. Lett. 61, 2756 (1988) ** I.N.Onishchenko, V.A.Kiselev, G.V.Sotnikov et al. Proc. 1995 Particle Accelerator Conf., p. 782-3*** T.B.Zhang, J.L.Hirshfield, T.C.Marshall et al Proc. 1997 Particle Accelerator Conf., V.42, No.3, p.1341

 
 
MOPLT103 Radiation Resistant Magnetic Sensors for Accelerators wiggler, electron, radiation, wakefield 773
 
  • I. Bolshakova, R. Holyaka
    LPNU, Lviv
  • S. Kulikov
    JINR, Dubna, Moscow Region
  • M. Kumada
    NIRS, Chiba-shi
  • C. Leroy
    CERN, Geneva
  The technology of obtaining the radiation resistant magnetic sensors, which characteristics remain stable under the irradiation with high dose of fast neutrons was designed. Radiation resistant sensors are developed on the base of InSb. While irradiation with neutron flux of 1010 n*cm-2*c-1 with energies 0.1…13 MeV, with the thermal neutrons part in the general flux of 20% and intermediate fluxes of 25%, the main sensors’ characteristics, that is their sensitivity to the magnetic field, change no more than for 0.05% up to the fluence of 1*1015 n*cm-2 and no more than for 1% up to the fluence of 3*1016 n*cm-2. Radiation resistant sensors are used for development of magnetic field monitoring system with measuring channels accuracy of 0,01%, which have a function of temperature measurement with the accuracy of 0.1 С at the place of sensor location, moreover, it has self diagnostics and self correction functions. This system passed the long-term testing of continuous 3 months operation at the Neutron Physics Laboratory, JINR, Dubna at the IBR-2 neutron reactor.  
 
MOPLT104 Quantitative Optimisation Studies of the Muon Front-End for a Neutrino Factory wiggler, electron, radiation, wakefield 776
 
  • S.J. Brooks
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  In a Neutrino Factory, short proton pulses hit a target, producing pions at widely varying angles and energies. Efficient pion capture is required to maximise the yield of decayed muons, which proceed via acceleration stages into a muon storage ring to produce neutrinos. This paper presents optimisation of a solenoidal decay channel designed for high-emittance pions, based on schemes from CERN and RAL. A non-linear tracking code has been written to run under an optimisation algorithm where every beamline element can be varied, which is then deployed as a distributed computing project. Some subsequent stages of muon beamline are also simulated, including RF and non-RF phase-rotation techniques and in one option, initial muon acceleration to 400MeV. The objective is to find optimal transmissions for each front-end concept.  
 
MOPLT105 Implementation of MICE at RAL wiggler, electron, radiation, wakefield 779
 
  • P. Drumm
    CCLRC/RAL/ISIS, Chilton, Didcot, Oxon
  The Muon Ionisation Cooling Experiment (MICE) is motivated by the vision of the neutrino factory (NF). The cost and practicality of the NF depends on an early control of the emittance of the muon beam that will be accelerated and stored to produce the neutrino beams. A number of possibilities for transverse cooling of the emittance have been proposed including ionisation cooling. In such a concept, the muon beam is alternatively slowed down in cryogenic absorbers (energy loss by ionisation) and then re-accelerated in RF cavities to replace the lost energy. This process reduces the transverse momentum of the beam while maintaining the average momentum in the z-direction. The energy absorbing material should be characterised by a high stopping power and low multiple scattering: The material of choice is liquid hydrogen. MICE will replicate a piece of the NF cooling channel. The engineering of a safe system with thin windows for the containment of the liquid hydrogen and other features needed to safely operate will test the practical application of the cooling scheme and its performance. MICE is proof of principle for this untried technology. The paper reviews progress in MICE and the plans for its implementation at RAL.

The MICE Collaboration

 
 
MOPLT106 MICE: the Muon Ionisation Cooling Experiment wiggler, electron, radiation, wakefield 782
 
  • M. Ellis
    Imperial College of Science and Technology, Department of Physics, London
  The provision of intense stored muon beams would allow the properties of neutrinos to be measured precisely and provide a route to multi-TeV lepton-anti-lepton collisions. The short muon-lifetime makes it impossible to employ traditional cooling techniques while maintaining the muon-beam intensity. Ionisation cooling, a process in which the muon beam is passed through a series of liquid hydrogen absorbers followed by accelerating RF-cavities, is the proposed cooling technique. The international Muon Ionisation Cooling Experiment (MICE) collaboration proposes to perform an engineering demonstration of ionisation cooling. The MICE cooling channel, the instrumentation and the implementation at the Rutherford Appleton Laboratory is described together with the predicted performance of the channel and the measurements that will be made.  
 
MOPLT107 Nanosecond-timescale Intra-bunch-train Feedback for the Linear Collider: Results of the FONT2 Run feedback, wiggler, electron, radiation 785
 
  • P. Burrows, T. Hartin, S.M. Hussain, S. Molloy, G.R. White
    Queen Mary University of London, London
  • C. Adolphsen, J.C. Frisch, L. Hendrickson, R.K. Jobe, T. Markiewicz, D.J. McCormick, J. Nelson, M.C. Ross, S. Smith, T.J. Smith
    SLAC, Menlo Park, California
  • R. Barlow, M. Dufau, A. Kalinin
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • G. Myatt, C. Perry
    OXFORDphysics, Oxford, Oxon
  We report on experimental results from the December 2003/January 2004 data run of the Feedback On Nanosecond Timescales (FONT) experiment at the Next Linear Collider Test Accelerator at SLAC. We built a second-generation prototype intra-train beam-based feedback system incorporating beam position monitors, fast analogue signal processors, a feedback circuit, fast-risetime amplifiers and stripline kickers. We applied a novel real-time charge-normalisation scheme to account for beam current variations along the train. We used the system to correct the position of the 170 nanosecond-long bunchtrain at NLCTA, in both 'feed forward' and 'feedback' modes. We achieved a latency of 53 nanoseconds, representing a significant improvement on FONT1 (2002), and providing a demonstration of intra-train feedback for the Linear Collider.  
 
MOPLT108 TESLA Linac-IP Simulations wiggler, radiation, luminosity, acceleration 788
 
  • G.R. White
    Queen Mary University of London, London
  • D. Schulte
    CERN, Geneva
  • N.J. Walker
    DESY, Hamburg
  We have formulated integrated simulations of the transport of the electron and positron bunches in the Linear Collider from the linac entrance through the beam delivery system and the interaction region, taking wakefield effects into account. We have set up the simulations to run on the 64-cpu prototpye Grid cluster at QMUL and generated results for various sets of input parameters for the TESLA and NLC machines. For TESLA we have evaluated the distortion of the phase-space of the bunches at the interaction point due to wakefields. We have calculated the luminosity degradation and the production of photons and e+e- pairs. We have simulated the performance of the intra-train beam feedback systems based on bunch position, angle and luminosity measures, and have evauated the luminosity recovery potential of these systems for TESLA and NLC.  
 
MOPLT109 Longitudinal Schottky Spectra of Bunched Beams wiggler, radiation, luminosity, acceleration 791
 
  • V. Balbekov, S. Nagaitsev
    Fermilab, Batavia, Illinois
  In this paper we derive an expression for longitudinal Schottky spectrum of a bunched beam in a stationary bucket. The expression is then used to calculate longitudinal emittance of the antiproton beam in the Fermilab Recycler ring. The Recycler beam is bunched longitudinally by a barrier-bucket rf waveform. Under certain bucket conditions, dependence of synchrotron frequency on particle energy becomes non-monotonic. It complicates the Schottky spectrum derivation and interpretation; we address these difficulties in our paper.  
 
MOPLT110 Stochastic Cooling in Barrier Buckets at the Fermilab Recycler wiggler, radiation, luminosity, acceleration 794
 
  • D.R. Broemmelsiek, M. Hu, S. Nagaitsev
    Fermilab, Batavia, Illinois
  The Fermilab Recycler is a fixed 8-GeV kinetic energy storage ring located in the Fermilab Main Injector tunnel near the ceiling. The role of stochastic cooling in the Recycler is to pre-cool the transverse phase-space of injected antiprotons for efficient electron cooling. This requires a gated stochastic cooling system working on beam confined in a barrier bucket. The performance of this system is reviewed. In addition, a study of the cooling rates and asymmptotic emittances as a function of beam intensity is presented.  
 
MOPLT156 High Brightness Electron Guns for Next-Generation Light Sources and Accelerators ion, luminosity, acceleration, vacuum 899
 
  • H. Bluem, M.D. Cole, J. Rathke, T. Schultheiss, A.M.M. Todd
    AES, Princeton, New Jersey
  • I. Ben-Zvi, T. Srinivasan-Rao
    BNL, Upton, Long Island, New York
  • P. Colestock, D.C. Nguyen, R.L. Wood, L. Young
    LANL, Los Alamos, New Mexico
  • D. Janssen
    FZR, Dresden
  • J. Lewellen
    ANL, Argonne, Illinois
  • G. Neil, H.L. Phillips, J.P. Preble
    Jefferson Lab, Newport News, Virginia
  Advanced Energy Systems continues to develop advanced electron gun and injector concepts. Several of these projects have been previously described, but the progress and status of each will be updated. The project closest to completion is an all superconducting RF (SRF) gun, being developed in collaboration with the Brookhaven National Laboratory, that uses the niobium of the cavity wall itself as the photocathode material. This gun has been fabricated and will shortly be tested with beam. The cavity string for a closely-coupled DC gun and SRF cavity injector that is expected to provide beam quality sufficient for proposed ERL light sources and FELs will be assembled at the Jefferson Laboratory later this year. We are also collaboration with Los Alamos on a prototype CW normal-conducting RF gun with similar performance, that will undergo thermal testing in late 2004. Another CW SRF gun project that uses a high quantum efficiency photocathode, similar to the FZ-Rossendorf approach, has just begun. Finally, we will present the RF design and cold test results for a fully axisymmetric, ultra-high-brightness x-band RF gun.  
 
MOPLT158 Cost Optimization of Non-Scaling FFAG Lattices for Muon Acceleration ion, luminosity, vacuum, quadrupole 902
 
  • J.S. Berg, R. Palmer
    BNL, Upton, Long Island, New York
  Fixed Field Alternating Gradient (FFAG) accelerators are a promising idea for reducing the cost of acceleration for muon accelerators as well as other machines. This paper presents an automated method for designing these machines to certain specifications, and uses that method to find a minimum cost design. The dependence of this minimum cost on various input parameters to the system is given. The impact of the result on an FFAG design for muon acceleration is discussed.  
 
MOPLT159 RF Techniques for Improved Luminosity at RHIC vacuum, quadrupole, beamloading, undulator 905
 
  • J.M. Brennan, M. Blaskiewicz, J. Butler, J. DeLong, W. Fischer, T. Hayes
    BNL, Upton, Long Island, New York
  The Relativistic Heavy Ion Collider has improved its luminosity performance significantly in the course of the first three physics runs. A number of special techniques for the operation of the rf systems have been developed to facilitate these improvements. Herein we describe these techniques, which include: an ultra low-noise rf source for the 197 MHz storage cavities; synchronization of the two rings during acceleration (including crossing the transition energy) to avoid spurious collisions on the ramp, which modulate the beam-beam tune shift; a frequency shift switch-on technique for transferring bunches from the acceleration to the storage rf systems; installation of dedicated 200 MHz cavities to provide longitudinal Landau damping on the ramp, and automated corrections to longitudinal injection parameters to minimize emittance growth.  
 
MOPLT162 Continuous Abort Gap Cleaning at RHIC vacuum, quadrupole, beamloading, undulator 908
 
  • K.A. Drees, R.P. Fliller III, W. Fu, R. Michnoff
    BNL, Upton, Long Island, New York
  Since the RHIC Au-Au run in the year 2001 the 200 MHz cavity system was used at storage and a 28 MHz system during injection and acceleration.The rebucketing procedure potentially causes a higher debunching rate of heavy ion beams in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam can easily account for more than 30% of the total beam intensity. This effect is even stronger with the achieved high intensities of the RHIC run 2004. A beam abort at the presence of a lot of debunched beam bears the risk of magnet quenching and experimental detector damage due to uncontrolled beam losses. Thus it is desirable to avoid any accumulation of debunched beam from the beginning of each store, in particular to anticipate cases of unscheduled beam aborts due to a system failure. A combination of a fast transverse kicker and the new 2-stage copper collimator system is used to clean the abort gap continuously throughout the store with a repetition rate of 1 Hz. This report gives an overview of the new gap cleaning procedure and the achieved performance.  
 
MOPLT163 Luminosity Optimization Using Automated IR Steering at RHIC vacuum, quadrupole, luminosity, beamloading 911
 
  • K.A. Drees, T. D'Ottavio
    BNL, Upton, Long Island, New York
  The goal of the RHIC 2004 Au-Au run was to maximize the achieved integrated luminosity. One way is to increase beam currents and minimize beam transverse emittances. Another important ingredient is the minimization of time spent on activities postponing the declaration of 'physics conditions', i.e. stable beam conditions allowing the experimental detectors to take data. Since collision rates are particularly high in the beginning of the store the integrated luminosity benefits considerably from any minute saved early in the store. In the RHIC run 2004 a new IR steering application uses luminosity monitor signals as a feedback for a fully automated steering procedure. This report gives an overview of the used procedure and summarizes the achieved results.  
 
MOPLT164 Bunch Patterns and Pressure Rise in RHIC vacuum, quadrupole, beamloading, undulator 914
 
  • W. Fischer, U. Iriso
    BNL, Upton, Long Island, New York
  The RHIC luminosity is limited by pressure rises with high intensity beams. At injection, the dominating cause for the pressure rise was shown to be electron clouds. We discuss the distributions of bunches along the circumference that minimize the electron cloud effect in RHIC. Experimental data are compared with simulation results, and experiences at the B-factories.  
 
MOPLT165 Luminosity Increases in Gold-gold Operation in RHIC luminosity, vacuum, quadrupole, beamloading 917
 
  • W. Fischer, L. Ahrens, J. Alessi, M. Bai, D. Barton, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, D. Bruno, J. Butler, R. Calaga, P. Cameron, R. Connolly, T. D'Ottavio, J. DeLong, K.A. Drees, W. Fu, G. Ganetis, J. Glenn, T. Hayes, P. He, H.-C. Hseuh, H. Huang, P. Ingrassia, U. Iriso, R. Lee, Y. Luo, W.W. MacKay, G. Marr, A. Marusic, R. Michnoff, C. Montag, J. Morris, T. Nicoletti, B. Oerter, C. Pearson, S. Peggs, A. Pendzick, F.C. Pilat, V. Ptitsyn, T. Roser, J. Sandberg, T. Satogata, C. Schultheiss, A. Sidi-Yekhlef, L. Smart, S. Tepikian, R. Tomas, D. Trbojevic, N. Tsoupas, J. Tuozzolo, J. Van Zeijts, K. Vetter, K. Yip, A. Zaltsman, S.Y. Zhang, W. Zhang
    BNL, Upton, Long Island, New York
  After an exploratory phase, during which a number of beam parameters were varied, the RHIC experiments now demand high luminosity to study heavy ion collisions in detail. Presently RHIC operates routinely above its design luminosity. In the first 4 weeks of its current operating period (Run-4) the machine has delivered more integrated luminosity that during the 14 weeks of the last gold-gold operating period (Run-2). We give an overview of the changes that increased the instantaneous luminosity and luminosity lifetime, raised the reliability, and improved the operational efficiency.  
 
MOPLT167 RHIC Operation with Longitudinally Polarized Protons luminosity, vacuum, quadrupole, beamloading 920
 
  • H. Huang, M. Bai, J. Beebe-Wang, M. Blaskiewicz, J.M. Brennan, K.A. Drees, W. Fischer, A.U. Luccio, W.W. MacKay, C. Montag, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, S. Tepikian, D. Trbojevic, J. Van Zeijts, A.Y. Zelinsky, S.Y. Zhang
    BNL, Upton, Long Island, New York
  Longitudinally polarized proton beams have been accelerated, stored and collided at 100GeV in the Relativistic Heavy Ion Collider (RHIC) to study spin effects in the hadronic reactions. The essential equipment includes four Siberian snakes, eight spin rotators and a fast relative polarimeters in each of the two RHIC rings as well as local polarimeters at the STAR and PHENIX detectors. This paper summarizes the performance of RHIC as a polarized proton collider.  
 
MOPLT170 eRHIC, Future Electron-ion Collider at BNL electron, ion, vacuum, quadrupole 923
 
  • V. Ptitsyn, L. Ahrens, M. Bai, J. Beebe-Wang, I. Ben-Zvi, M. Blaskiewicz, J.M. Brennan, R. Calaga, X. Chang, E.D. Courant, A. Deshpande, A.V. Fedotov, W. Fischer, H. Hahn, J. Kewisch, V. Litvinenko, W.W. MacKay, C. Montag, S. Ozaki, B. Parker, S. Peggs, T. Roser, A. Ruggiero, B. Surrow, S. Tepikian, D. Trbojevic, V. Yakimenko, S.Y. Zhang
    BNL, Upton, Long Island, New York
  • D.P. Barber
    DESY, Hamburg
  • M. Farkhondeh, W. Franklin, W. Graves, R. Milner, C. Tschalaer, J. Van der Laan, D. Wang, F. Wang, A. Zolfaghari, T. Zwart
    MIT/BLAC, Middleton, Massachusetts
  • A.V. Otboev, Y.M. Shatunov
    BINP SB RAS, Novosibirsk
  The paper reviews the progress made lately in the design of eRHIC, proposed future electron-ion collider on the basis of the existing RHIC machine. The eRHIC aims to provide collisions of electrons and positrons on ions and protons in center mass energy range of 25-70 GeV. The goal luminosities are in 1032-1033 1/(s*cm2) values for e-p and in 1030-1031 1/(s*cm2) values for e-Au collisions. An essential design requirement is to provide longitudinally polarized beams of electrons and protons (and, possibly lighter ions) at the collision point. The eRHIC ZDR has been recently developed which considers various aspects of the accelerator design. An electron accelerator, which delivers about 0.5A polarized electron beam current in the electron energy range of 5 to 10 GeV, should be constructed at the BNL near existing ion rings of the RHIC collider and should intersect an ion ring at least in one of the available ion ring interaction regions. In order to reach the luminosity goals some upgrades in ion rings also would be required. Ways to reach lower beam emmittances (electron cooling) and higher beam intensities have to be realized.  
 
MOPLT171 A Pratical Demonstration of the CRFQ Storage Ring electron, vacuum, beamloading, undulator 926
 
  • A. Ruggiero
    BNL, Upton, Long Island, New York
  • L. Campajola, V.G. Vaccaro
    Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli
  • D. Davino
    Universita' degli Studi del Sannio, Benevento
  • M.R. Masullo
    INFN-Napoli, Napoli
  The Circular Radiofrequency Quadrupole (CRFQ) is a new concept of a storage and accelerator ring for intense beams of light and heavy ions, protons and electrons. It is basically a Linear Radio-Frequency Quadrupole completely bent on a circle. The advantages are expected to be equivalent to those of a Linear RFQ, namely higher beam intensity and smaller beam dimensions. Moreover, it is a more compact device when compared to conventional accelerators. A collaboration was created between Brookhaven National Laboratory, the University of Naples, the University of Sannio, and the INFN-Section of Naples (Italy) for the purpose of developing a proof of principle (PoP) of the CRFQ. During the initial stage the main goal is the demonstration of the curvature effect of the quadrupolar RFQ field. At that purpose, the project is actually conceived of three phases: (i) develop an adequate 30 keV proton source, (ii) design, manufacture and test a linear RFQ section, and (iii) design, manufacture and test a curved RFQ section, both operating at 200 MHz. The linear section acts as a matching with the ion source at one end, and the curved section at the other. The paper discusses mechanical and RF considerations during the design and experiment. The final goal of the collaboration is eventually to build enough curved sections to complete the storage ring where to demonstrate storage of 30 keV protons over long periods of time.  
 
MOPLT172 Quest for a New Working Point in RHIC electron, vacuum, beamloading, undulator 929
 
  • R. Tomas, M. Bai, W. Fischer, V. Ptitsyn, T. Roser, T. Satogata
    BNL, Upton, Long Island, New York
  The beam-beam interaction is a limiting factor in RHIC's performance, particularly in proton operation. Changing the working point is a strategy to minimize the beam-beam effect and improve the performance of the machine. Experiments at injection energy and simulations have been performed for a set of working points in order to determine what are the best candidates.  
 
MOPLT174 Electron Acceleration for e-RHIC with the Non-scaling FFAG vacuum, beamloading, undulator, hadron 932
 
  • D. Trbojevic, M. Blaskiewicz, E.D. Courant, J. Kewisch, T. Roser, A. Ruggiero, N. Tsoupas
    BNL, Upton, Long Island, New York
  A non-scaling FFAG lattice design to accelerate electrons from 3.2 to 10 GeV is described. This is one of the possible solutions for the future electron-ion collider (eRHIC) at Relativistic Heavy Ion Collier (RHIC) at Brookhaven National Laboratory (BNL). This e-RHIC proposal requires acceleration of the low emittance electrons up to energy of 10 GeV. To reduce a high cost of the full energy super-conducting linear accelerator an alternative approach with the FFAG is considered. The report describes the 1277 meters circumference non-scaling FFAG ring. The Courant-Snyder functions, orbit offsets, momentum compaction, and path length dependences on momentum during acceleration are presented.  
 
MOPLT175 A Method to Measure the Focusing Properties (R_Matrix) of a Magnet vacuum, focusing, beamloading, undulator 935
 
  • N. Tsoupas, L. Ahrens, K.A. Brown, D. Gassner, J. Glenn, Y.Y. Lee, T. Roser, P. Thieberger, J. Wei
    BNL, Upton, Long Island, New York
  We discuss a method that may be used to measure the focusing properties of a magnet. This method may prove valuable when applied to non-conventional magnets that deviate from the usual dipole magnets or other multipole magnets which are commonly used in a synchrotron. In this category of non-conventional magnets, fall special magnets, which come under the name Snakes. Such magnets are being used in synchrotron accelerators[*,**] to introduce artificial spin resonances to help overcome the intrinsic and/or imperfection spin resonances. This method of measuring the focusing properties of a magnet requires the use of low energy and high rigidity heavy-ions which may be obtained from the BNL Tandem accelerator.In brief the method consists on, injecting low emittance beamlets of lightly stripped heavy ions into a magnet and measuring the coordinates, of these narrowbeamlets, at the entrance and exit of the magnet.From the measurement of these coordinates of the narrowbeamlets we can deduce information on the R matrix and higher order matrix elements that define the focusing properties of the magnet.

* T. Roser, AIP Conf. Proc. 187 (1988) 1221** H.Huang, et. al. Phys. Rev. Lett. 73 (1994) 2982

 
 
MOPLT176 Mechanism of Electron Multipacting with a Long Bunch Proton Beam vacuum, electron, focusing, beamloading 938
 
  • L. Wang, M. Blaskiewicz, J. Wei
    BNL, Upton, Long Island, New York
  • R.J. Macek
    LANL/LANSCE, Los Alamos, New Mexico
  The mechanism of electron multipacting in long bunched proton machine has been quantitatively described by the electron energy gain and electron motion. Some important parameters related to electron multipacting are investigated in detail. It is proved that multipacting is sensitive to beam intensity, longitudinal beam profile shape and transverse beam size. Agreement is achieved among our analysis, simulation and experiment.  
 
MOPLT177 Stochastic Cooling Power Requirements vacuum, electron, focusing, beamloading 941
 
  • J. Wei, M. Blaskiewicz, J.M. Brennan
    BNL, Upton, Long Island, New York
  A practical obstacle for stochastic cooling in high-energy colliders is the large amount of power needed for the cooling system. This paper discusses the cooling power needed for the longitudinal cooling process. Based on the coasting-beam Fokker-Planck equation, we analytically derived the optimum cooling rate and cooling power for a beam of uniform distribution and a cooling system of linear gain function. The results indicate that the usual back-of-envelope formula over-estimated the cooling power by a factor of the mixing factor $M$. On the other hand, the scaling laws derived from the coasting-beam Fokker-Planck approach agree with those derived from the bunched-beam Fokker-Planck approach if the peak beam intensity is used as the effective coasting-beam intensity. A longitudinal stochastic cooling system of 4 – 8 GHz bandwidth in RHIC can effectively counteract intrabeam scattering, preventing the beam from escaping the RF bucket becoming debunched around the ring.  
 
MOPLT178 RHIC Pressure Rise vacuum, ion, focusing, beamloading 944
 
  • S.Y. Zhang, J. Alessi, M. Bai, M. Blaskiewicz, P. Cameron, K.A. Drees, W. Fischer, R.P. Fliller III, D. Gassner, J. Gullotta, P. He, H.-C. Hseuh, H. Huang, U. Iriso, R. Lee, Y. Luo, W.W. MacKay, C. Montag, B. Oerter, S. Peggs, F.C. Pilat, V. Ptitsyn, T. Roser, T. Satogata, L. Smart, P. Thieberger, D. Trbojevic, J. Van Zeijts, L. Wang, J. Wei, K. Zeno
    BNL, Upton, Long Island, New York
  Beam induced pressure rise remains an intensity limit at the RHIC for both heavy ion and polarized proton operations. The beam injection pressure rise at warm sections has been diagnosed due to electron cloud effect. In addition, pressure rise of heavy ion operation at the beam transition has caused experiment background problem in deuteron-gold run, and it is expected to take place in gold-gold run at high intensities. This type of pressure rise is related to beam momentum spread, and the electron cloud seems not dominant. Extensive approaches for both diagnosis and looking-for-remedies are undergoing in the current gold operation, RUN 4. Results of beam scrubbing, NEG pipe in RHIC ring, beam scraping test of ion desorption, beam momentum effect at the transition, beam gap effect, solenoid effect, and NEG pipe ion desorption test stand will be presented.  
 
MOPLT179 Beam Scrubbing for RHIC Polarized Proton Opearation vacuum, ion, focusing, proton 947
 
  • S.Y. Zhang, W. Fischer, H. Huang, T. Roser
    BNL, Upton, Long Island, New York
  One of the intensity limiting factor of RHIC polarized proton beam is the electron cloud induced pressure rise. During the 2003 polarized proton run, a beam scrubbing study was performed. Actual beam scrubbing time was much less than the planned 2 hours. However, a non-trivial beam scrubbing effect was observed not only in the locations with highest pressure rise, but also in most of the single beam straight sections. This not only confirmed that beam scrubbing is indeed a countermeasure to the electron cloud, but also showed the feasibility of applying beam scrubbing in RHIC proton beam operation to allow for higher beam intensities. In this article, the results will be reported.  
 
TUXCH01 Review of ISOL-type Radioactive Beam Facilities vacuum, ion, focusing, beamloading 45
 
  • M. Lindroos
    CERN, Geneva
  The ISOL technique was invented in Copenhagen over 50 years ago and eventually migrated to CERN where a suitable proton drive beam was available at the Syncho-Cyclotron. The quick spread of the technique from CERN to many other laboratories has resulted in a large user community, which has assured the continued development of the method, physics in the front-line of fundamental research and the application of the method to many applied sciences. The technique is today established as one of the main techniques for on-line isotope production of high intensity and high quality beams. The thick targets used allows the production of unmatched high intensity radioactive beams. The fact that the ions are produced at rest makes it ideally suitable for low energy experiments and for post acceleration using well established accelerator techniques. The many different versions of the technique will be discussed and the many facilities spread all over the world will be reviewed. The major developments at the existing facilities and the challenges encountered will be presented. Finally, the possibility of using the resulting high intensity beams for the production of intense neutrino beams will be briefly discussed.  
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TUXCH02 FAIR - An International Accelerator Facility for Research with Ions and Antiprotons vacuum, ion, focusing, beamloading 50
 
  • W.F. Henning
    GSI, Darmstadt
  This presentation describes the conceptual design for the accelerator facility and the physics research program, and discusses the status and the new challenges in accelerator physics and technology.  
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TUYACH01 Laser-acceleration and Laser-cooling for Ion Beams vacuum, focusing, laser, acceleration 54
 
  • M. Roth, A. Blazevic, E. Brambrink, M. Geissel
    TU Darmstadt, Darmstadt
  • P. Audebert
    LULI, Palaiseaux
  • M. Bussmann, D. Habs, U. Schramm, J. Schreiber
    LMU, München
  • R. Clarke, S. Karsch, D. Neely
    CCLRC/RAL, Chilton, Didcot, Oxon
  • J.A. Cobble, J. Fernandez, M. Hegelich, S. Letzring
    LANL, Los Alamos, New Mexico
  • T.E. Cowan, J. Fuchs, A. Kemp, H. Ruhl
    University of Nevada, Reno, Reno, Nevada
  • K. Ledingham, P. McKenna
    Strathclyde University, Glasgow
  The acceleration or cooling of particles with lasers has been the subject of growing interest over the last years. Because of the huge difference in mass, the acceleration of ions was so far limited to thermal expansion from laser plasmas, driven by the hot electron temperature. In recent years, due to the development of short-pulse ultra-intense lasers, the manipulation of ions has now become possible. Especially the generation of high quality, intense ion beams from laser solid interaction has attracted large attention and is investigated at many laboratories world-wide. For the first time, intense, directed, low emittance beams of ions have been observed, having several MeV of particle energy right from the source. A wealth of applications including next generation ion sources can be envisioned. The talk will give an overview of the status of laser cooling and ion acceleration including the last experimental results. In addition, an overview of the current and future research activities will be presented.  
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TUYBCH01 Design Criteria and Technology Challenges for the Undulators of the Future radiation, undulator, focusing, laser 59
 
  • H. Kitamura, T. Hara, X. Maréchal, T. Tanaka
    RIKEN Spring-8 Harima, Hyogo
  • T. Bizen, T. Seike
    JASRI/SPring-8, Hyogo
  Nowadays, undulators are essential devices for synchrotron radiation (SR) facilities since they generate a quasi-monochromatic radiation with various features, high brightness , high energy and special polarization characteristics. Particularly, demands for high-energy radiation in the X-ray region have become much stronger in many research fields. Accordingly, a short-period undulator design has been developed, because they increase the number of periods in a unit undulator length and as a consequence, they generate brilliant synchrotron radiation. Also, short undulator periodicity enables emission of high-energy photons, and it opens the way for X-ray beamline operation in medium size synchrotron radiation facilities, such as SLS, NSLS, PLS, CLS, ALS, SOLEIL, DIAMOND, SPEAR-III and so on. From the same reason, a short-period undulator is very attractive for SASE-FEL or ERL facilities, since it lowers the electron beam energy necessary for X-ray operation. As a result this design makes a whole facility design compact and economic. In the talk, I will review the status of the development on short-period undulators of various types (in-vacuum, superconducting and cryogenic types) and describe the future direction.  
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TUYBCH02 Technological Challenges for High Brightness Photo-injectors radiation, undulator, focusing, laser 64
 
  • G. Suberlucq
    CERN, Geneva
  Many applications, from linear colliders to free-electron lasers, passing through light sources and many other electron sources, require high brightness electron beams, usually produced by photo-injectors. Because certain parameters of these applications differ by several orders of magnitude, various solutions were implemented for the design and construction of the three main parts of the photo-injectors: lasers, photocathodes and guns. This paper summarizes the different requirements, how they lead to technological challenges and how R&D programs try to overcome these challenges. Some examples of state-of-the-art parts are presented.  
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TUZACH01 Positron Source Options for Linear Colliders positron, focusing, synchrotron, acceleration 69
 
  • K. Floettmann
    DESY, Hamburg
  Linear colliders require sources delivering particle intensities much higher than sources for storage rings and even several orders of magnitude larger than the SLC positron source, the highest intensity positron source operated so far. A fundamental limitation for the intensity of a positron source is set by the thermal stress in the target. Besides improvements of conventional positron sources, i.e. sources where an electron beam creates electron position pairs in an electromagnetic cascade, new concepts based on the direct conversion of gamma radiation offer possibilities for increased particle intensities. In these sources the hard gamma radiation has to be produced either in an undulator or by backscattering of laser light off an electron beam. An additional advantage of gamma radiation based sources is the possibility to produce polarized positrons. The talk will give an overview of the developments of high intensity unpolarized and polarized positron sources for linear colliders.  
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TUZACH02 Ultra-high Gradient Compact Accelerator Developments injection, positron, focusing, plasma 74
 
  • G.J.H. Brussaard, M.J. Van der Wiel
    TUE, Eindhoven
  Continued development of relatively compact, although not quite 'table-top', lasers with peak powers in the range up to 100 TW has enabled laser-plasma-based acceleration experiments with amazing gradients of up to 1 TV/m. In order to usefully apply such gradients to 'controlled' acceleration, various hurdles need to be overcome. The main one is that of well-synchronized injection into a sub-mm to micron wavelength plasma wave. The talk will describe the various physics regimes of laser wakefield acceleration, and the two classes of experiments being pursued. One is that of atmospheric-density plasmas, non-linear wakefields with extreme gradients (hundreds of GV/m)and 'internal injection' of few-femtosecond electron bunches. A second class involves modest-density plasmas,wakefields of order 1 GV/m and external injection of (sub)-ps bunches. The state-of-the-art of these experiments will be covered, including the progress on plasma waveguiding of TW pulses over many diffraction lengths. The talk will also provide an outlook for the coming few years. This part includes proposed schemes for improvements in the area of injection, such as 'all-optical' injection and injection based on GV/m 'pulsed-DC' photoguns.  
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TUZBCH01 Beam Quality Preservation in the CERN PS-SPS Complex positron, focusing, plasma, synchrotron 78
 
  • G. Arduini
    CERN, Geneva
  The LHC will require beams of unprecedented transverse and longitudinal brightness. Their production imposes tight constraints on the emittance growth in each element of the LHC injector chain, namely the PS-SPS Accelerator Complex. The problems encountered at the different stages of the acceleration in the complex span a wide range of topics, such as injection matching, RF gymnastics, space charge, transverse and longitudinal single- and coupled-bunch instabilities, and electron cloud effects. The measurement techniques developed and applied to identify and study the various sources of emittance dilution to the high precision required for the LHC beams and the solutions found to control such phenomena are illustrated.  
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TUZBCH02 Beam Dynamics Challenges for Future Circular Colliders positron, focusing, plasma, synchrotron 83
 
  • F. Zimmermann
    CERN, Geneva
  The luminosity of circular colliders rises with the beam intensity, until some limit is encountered, mostly due to head-on and long-range beam-beam interaction, due to electron cloud, or due to conventional impedance sources. These limitations can be alleviated, if not overcome, by a proper choice of beam parameters and by dedicated compensation schemes. Examples include the alternating crossing at several interaction points, electromagnetic wires, super-bunches, electron lenses, clearing electrodes, and nonlinear collimation. I illustrate the benefit from such mitigating measures for the Tevatron, the LHC, the LHC Upgrade, the VLHC, the super e+e- factories, or other projects, and I describe related research efforts at FNAL, KEK, BNL and CERN.  
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TUXLH01 Machine Protection Issues and Strategies for the LHC positron, focusing, plasma, synchrotron 88
 
  • R. Schmidt, J. Wenninger
    CERN, Geneva
  For nominal beam parameters at 7 TeV/c, each of the two LHC proton beams has a stored energy of 350 MJ threatening to damage accelerator equipment in case of uncontrolled beam loss. Since the beam dump blocks are the only element of the LHC that can withstand the impact of the full beam, it is essential for the protection of the LHC that the beams are properly extracted onto the dump blocks in case of emergency. The time constants for failures leading to beam loss extend from 100 microseconds to few seconds. Several protection systems are designed to ensure safe operation, such as beam instrumentation, collimators and absorbers, and magnet protection. Failures must be detected at a sufficiently early stage and transmitted to the beam interlock system that triggers the beam dumping system. The strategy for the protection of the LHC will be illustrated starting from some typical failures.  
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TUXLH02 HERA Performance Upgrade: Achievements and Plans for the Future positron, focusing, plasma, luminosity 93
 
  • M.G. Minty
    DESY, Hamburg
  Having surpassed the design luminosity of 1.5 x 1031/cm2s already in 1997, an ambitious upgrade of the HERA proton-lepton collider was undertaken in 2000/2001 to provide both higher luminosity and longitudinally polarized lepton beams in the colliding beam experiments, H1 and ZEUS, and for the internal gas target experiment, HERMES. Routine operation following the upgrade has commenced. Initially experimental backgrounds limited the total beam currents so the number of colliding bunches was reduced while maintaining high single-bunch beam currents. With nominal, pre-upgrade, bunch currents the measured specific luminosity is 2.5 times higher than before, however about 15% smaller than design. Following modifications to alleviate the high backgrounds in 2003, HERA is now again operating with the design number of bunches and the total beam currents are being steadily increased. With only 40% of the total design current, peak luminosities of 2.5 x 1031/cm2s have been demonstrated with a longitudinal polarization of >40%. In this presentation the experiences from the upgrade commissioning will be reviewed. Plans for improvement and pronections for the future will be described.  
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TUXLH03 RHIC Performance and Plans Towards Higher Luminosity and Higher Polarization positron, focusing, plasma, proton 98
 
  • T. Satogata
    BNL, Upton, Long Island, New York
  RHIC is the first hadron collider consisting of two independent rings. It is designed to operate over a wide range of beam energies and species, including polarized protons, heavy ions, and asymmetric beam collisions. RHIC has produced physics data at four experiments since 1999 in runs that include gold-on-gold collisions at design beam energy (100 GeV/u), high-energy polarized proton-proton collisions (100 GeV on 100 GeV), and deuteron-gold collisions (100 GeV/u). Recent machine performance will be reviewed for high-luminosity gold-gold operations and polarized proton operations, including causes and solutions for known operational limits. Plans and progress for luminosity and polarization improvements, electron cooling, and the electron-ion collider eRHIC will be discussed.  
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TUYLH01 Proton and Ion Sources for High Intensity Accelerators positron, focusing, plasma, proton 103
 
  • R. Scrivens
    CERN, Geneva
  Future high intensity ion accelerators, including SNS, European Spallation Source, SPL etc, will require high current and high duty factor sources for protons, negative hydrogen and heavier ions. In order to achieve these goals, a comparison of the Electron Cyclotron Resonance, radio-frequency and Penning ion sources, among others, will be made. For each of these source types, the present operational sources will be compared to the state-of-the-art research devices with special attention given to reliability and availability. Finally, the future research and development aims will be discussed.  
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TUYLH02 Low and Medium Energy Beam Acceleration in High Intensity Linacs positron, focusing, plasma, synchrotron 108
 
  • J. Stovall
    LANL, Los Alamos, New Mexico
  In the past two years accelerator builders have published papers describing mature designs of no fewer than 7 new high-performance proton linacs. These machines are typically designed to deliver multi-megawatt beams for applications in pure and applied research. All of these machines use the radio-frequency quadrupole (RFQ) linac for the first stage of acceleration to reach an energy of a few MeV. In essentially all cases, superconducting elliptical cavities have been adopted as the technology of choice for acceleration above ~100 MeV. Between the RFQ and the high-energy elliptical cavities, designers have proposed no fewer than 6 different types of accelerating structures. In many cases these structures are reaching maturity as a result of active development programs. In this paper, we review the design architectures of the ?low and medium energy? portions of these machines emphasizing recent experience and developments applicable to high-current linac designs.  
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TUYLH03 Challenges facing the Generation of MW Proton Beams using Rapid Cycling Synchrotrons positron, focusing, plasma, radiation 113
 
  • Y. Irie
    KEK, Ibaraki
  The MW proton source using rapid cycling synchrotron (RCS) has many challenging aspects, such as (1) large aperture magnets and much higher RF voltages per turn due to a low energy injection and a large and rapid swing of the magnetic field, (2) field tracking between many magnet-families under slightly saturated conditions, (3) RF trapping with fundamental and higher harmonic cavities, (4) H- charge stripping foil, (5) large acceptance injection and extraction straights, (6) beam loss collection, and (7) beam instabilities. These are discussed in details mainly on the basis of the J-PARC 3GeV RCS, which is under construction in Japan. Issues (3) to (7) are common with another scheme of MW spallation neutron source, i.e. full-energy linac + accumulator ring. Comparisons with the SNS design in the US are then made. Reliability/availability of these machines is very important theme which finally determines the successful operations. From the experiences in the existing machines, we will discuss the factors necessary toward the better performance.  
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TUPKF001 Upgrade and Commissioning of the LNLS RF System positron, focusing, plasma, beamloading 950
 
  • R.H.A. Farias, N.P. Abreu, L.C. Jahnel, L. Liu, C. Pardine, P.F. Tavares
    LNLS, Campinas
  In this paper we present a report on the commissioning of the new RF system of the electron storage ring of the brazilian synchrotron radiation facility (LNLS).  
 
TUPKF002 TRIUMF ISAC II RF Control System Design and Testing positron, focusing, plasma, beamloading 953
 
  • M.P. Laverty, S.F. Fang, K. Fong
    TRIUMF, Vancouver
  The rf control system for the ISAC II superconducting cavities is a hybrid analogue/digital design which has undergone several iterations in the course of its development. In the current design, the cavity operates in a self-excited feedback loop, while phase locked loops are used to achieve frequency and phase stability. Digital signal processors are used to provide amplitude and phase regulation, as well as mechanical cavity tuning control. The most recent version also allows for the rapid implementation of operating firmware and software changes, which can be done remotely, if the need arises. This paper describes the RF control system and the experience gained in operating this system with a four-cavity test facility.  
 
TUPKF003 Industrial Production of the Eight Normal-conducting 200 MHz ACN Cavities for the LHC positron, focusing, plasma, beamloading 956
 
  • R. Losito, E. Chiaveri, R. Hanni, T.P.R. Linnecar, S. Marque, J. Tuckmantel
    CERN, Geneva
  The LHC-ACN RF system consists of 8 normal-conducting cavities and is designed to reduce beam losses in the LHC when injecting beams with longitudinal emittance > 0.7 eVs from the CERN SPS. The cavity design took into account the possibility of recuperating all the "ancillary" equipment (tuners, fundamental mode damper, High Order Mode (HOM) couplers) from the old CERN SPS 200MHz system. The cavities are made from OFE copper. The original ingots, procured in Austria, have been forged and pre-formed by pressing them with a 20 tons press, following a procedure defined and adapted for the unusual dimensions of these pieces. The raw components thus obtained were machined and then welded together with an electron beam. In order to get a good repeatability of the fundamental mode frequency across the eight cavities, a procedure has been established with the contractor for the final machining and welding leading to a spread in frequencies below ±20 kHz (< 0.01%). The cavities will be installed in the LHC when losses at high intensities become significant. In the meantime they are undergoing a surface treatment to clean the RF surface and will be stored.  
 
TUPKF004 First Results with a Fast Phase and Amplitude Modulator for High Power RF Application positron, focusing, plasma, beamloading 959
 
  • D. Valuch, H. Frischholz, J. Tuckmantel
    CERN, Geneva
  • C. Weil
    AFT, Backnang
  In a high energy and high power superconducting proton linac, it is more economical to drive several cavities with a single high power transmitter rather than to use one transmitter per cavity. This option has however the disadvantage of not permitting to individually control each cavity, which potentially leads to instabilities. Provided that it can be built at a reasonable cost, a fast phase & amplitude modulator inserted into each cavity feeder line can provide the necessary control capability. A prototype of such a device has been built, based on two fast and compact high power RF phase-shifters, magnetically biased by external coils. The design is described, together with the results obtained at high and low power levels.  
 
TUPKF005 Inductive Output Tube Based 300 kW RF Amplifiers for the Diamond Light Source positron, focusing, plasma, beamloading 962
 
  • J. Alex, M. Brudsche, M. Frei, M. Müller, A. Spichiger
    Thales Broadcast & Multimedia AG, Turgi
  • M. Jensen
    Diamond, Oxfordshire
  All currently operating synchrotron light sources use klystron amplifiers to generate the RF power for the accelerator cavities. In TV broadcasting systems on the other hand, Inductive Output Tubes (IOT)are replacing the classical klystron based systems in all new high power UHF transmitters. The Diamond Light Source will be the first synchrotron to be operated using IOTs. For each accelerating cavity a total of four IOTs will be combined with a waveguide combiner to achieve the RF power requirement of 300 kW at 500 MHz. All IOTs will be supplied from a common crowbarless high voltage power supply. Three such systems will be installed starting in October 2004. This paper gives an overview of the design of the amplifiers, including the first test results from the factory commissioning.  
 
TUPKF006 Custom Design of Medium Energy Linear Accelerator Systems positron, focusing, plasma, beamloading 965
 
  • K. Dunkel, M. Pekeler, C. Piel, H.P. Vogel, P. vom Stein
    ACCEL, Bergisch Gladbach
  Based on customer requirements ACCEL Instruments is designing and building medium energy turn-key Linear Accelerator Systems for scientific applications. Within this paper design and performance of third generation synchrotron light source electron injector linacs will be presented. Further the design of a medium energy light ion linear accelerator will be discussed. This light ion accelerator is designed with independently phased superconducting rf cavities for cw operation and acceleration of different particle species and a variable Energy output.  
 
TUPKF007 Series Fabrication Technologies for Normalconducting Linac and Storage Ring Cavities positron, focusing, plasma, beamloading 968
 
  • P. vom Stein, K. Dunkel, B. Griep, C. Piel, H.P. Vogel
    ACCEL, Bergisch Gladbach
  Twelve HOM damped 476 MHz single cell cavities have been delivered for PEP II and the production of several 805 MHz CCL modules for SNS has recently been finalised by ACCEL Instruments. Based on those two examples, required key technologies for cavity production will be introduced. Final prove of successful manufacturing is given by low level rf measurements. Results of those measurements for above mentioned projects will be presented within this paper.  
 
TUPKF008 Status of the HoBiCaT Superconducting Cavity Test Facility at BESSY positron, focusing, plasma, beamloading 970
 
  • J. Knobloch, W. Anders, J. Borninkhof, S. Jung, M. Martin, A. Neumann, D. Pflückhahn, M. Schuster
    BESSY GmbH, Berlin
  BESSY has recently constructed the HoBiCaT cryogenic test facility for superconducting TESLA cavity units, including all ancillary devices (helium tank, input coupler, tuner, magnetic shielding). It is designed to house two such units in a configuration similar to that envisaged for the superconducting CW linac of the BESSY FEL. These units are presently being fabricated, prepared and assembled by industry. HoBiCaT will be used to address many of the issues that must be considered prior to finalizing the design of the proposed linac. Rapid turn-around-tests permit the investigation of items such as RF regulation, microphonic detuning and cryogenic parameters/achievable pressure stability. These test will also serve as the first step towards qualifying the industrial production of assembled cavity units. The commissioning of HoBiCaT is scheduled for Spring 2004 and the current status is presented here.  
 
TUPKF009 RF Control of the Superconducting Linac for the BESSY FEL positron, focusing, plasma, beamloading 973
 
  • J. Knobloch, A. Neumann
    BESSY GmbH, Berlin
  In the BESSY-FEL superconducting linac, precise RF control of the cavities' voltage is imperative to maintain a bunch-to-bunch time jitter of less than 50 fs for synchronization in the HGHG section. The average beam loading is less than 1.5 kW/m and the cavity bandwidth is small so that high-gain RF feedback is required. Noise, in particular microphonic detuning, strongly impact the achievable level of control. Presented here are simulations of the cavity-feedback system, taking into account beam loading and noise sources such as measurement noise, microphonics and injection jitter. These simulations are used to estimate the resultant time and energy jitter of the bunches as they enter the HGHG section of the BESSY FEL.  
 
TUPKF010 Cryogenic Considerations for CW Operation of TESLA-type Superconducting Cavity Modules for the BESSY FEL positron, focusing, plasma, beamloading 976
 
  • J. Knobloch, W. Anders, X. Yu
    BESSY GmbH, Berlin
  The proposed BESSY FEL uses a CW superconducting driver linac to provide acceleration up to 2.3 GeV. Its design is based on well-established TESLA technology, originally intended for heat loads of order 1 W/m at 2.0 K. CW operation increases this load to levels of order 15 W/m at 1.8 K for a total heat load of 3 kW at 2.3 GeV (given conservative assumptions for the attainable Q-factor). Presented here is an analysis of the cryogenic layout, including two-phase-flow simulations of the 1.8-K helium which help identify the changes needed for reliable CW operation. A modified ‘‘CW'' module and helium distribution scheme is proposed.  
 
TUPKF011 First Tests of a HOM-Damped High Power 500MHz Cavity positron, focusing, plasma, beamloading 979
 
  • F. Marhauser, E. Weihreter
    BESSY GmbH, Berlin
  A prototype high power 500 MHz copper cavity with three tapered circular waveguides for broadband higher order mode (HOM) damping has been fabricated especially for the use in 3rd generation synchrotron radiation sources. Low power impedance measurements are presented and compared with theoretical simulations to verify the expected HOM damping efficiency as well as the fundamental mode shunt impedance. After a careful cleaning and baking process to reduce the vacuum pressure the cavity has been conditioned at high power. All relevant parameters of the cavity are reported.  
 
TUPKF012 A HOM Damped Planar Accelerating Structure positron, damping, focusing, plasma 982
 
  • A. Blednykh, H. Henke
    TET, Berlin
  The problem of very fast higher order mode (HOM) suppression, in the order of 1ns, was investigated for a planar 30GHz accelerating structure. Both, damping and detuning were considered. A sufficient suppression could be achieved by damping waveguides in every cell in vertical and in horizontal direction. Finally, a scaled-up 10GHz model was built. It is a 35 cm long aluminum structure, which was machined by high-precision milling. In order to reduce the surface gradient on the input/output coupling irises a symmetrical RF coupler was developed. The HOM damping is accomplished by coupling six damping waveguides to each accelerating cell. The waveguides are loaded by a low resitivity RF load. The whole structure with waveguides and loads was optimized by means of the computer code GdfidL. The paper gives the design criteria and the results of s-parameter and bead-pull measurements.  
 
TUPKF013 Studies on Maximum RF Voltages in Ferrite-tuned Accelerating Cavities positron, damping, focusing, plasma 985
 
  • K. Kaspar, H.G. Koenig, T. Winnefeld
    GSI, Darmstadt
  The GSI SIS100 project requires very high accelerating voltages. With ferrite-tuned synchrotron cavities the gap voltage is often strongly limited by the Q-loss effect appearing at medium dc bias fields. At low bias fields, considerably higher voltages can be reached, however. The maximum usable amplitudes over the bias region have been studied. At zero bias, the ferrites could be driven to more than a factor 3 above the Q-loss limit. Except overheating, no other problems appeared. With increasing bias, the maximum amplitudes decrease continuously to the Q-loss level. In this fall-off region there is still a tuning factor up to 2.5 available, with rf flux densities by at least a factor 2 above the Q-loss level. Measurements on small samples of the ferrite material used in the GSI cavities could be verified very well in a full-size cavity, for the most part. The tests were mainly limited by the available anode voltage and the fear of damaging the cavity. It seems possible, to generalize the main results for other ferrite materials, also. Based on the results, a possible scenario for the SIS100 rf system is given. Additionally, the results lead to an alternative cavity design for higher voltages, which is described as well.  
 
TUPKF014 Electromagnetic Design of New RF Power Couplers for the S-DALINAC positron, damping, focusing, plasma 988
 
  • M. Kunze, W.F.O. Müller, T. Weiland
    TEMF, Darmstadt
  • M.B. Brunken, H.-D. Gräf, A. Richter
    TU Darmstadt, Darmstadt
  New rf power couplers for the Superconducting Darmstadt Linear Accelerator (S-DALINAC) injector have to be designed to transfer rf power up to 2 kW to the electron beam. This allows injector operation at beam currents from 0.15 mA to 0.2 mA and electron energies up to 14 MeV. The new couplers should possibly provide a variable external Q in the range from 5·106 to 3·109 and a small transverse kick. A variable coupling is needed to allow for perfect matching in the case of beam loading and when no beam is present, respectively. The second operation stage is used for cavity diagnostics. The asymmetric field distribution of the couplers generates emittance growth of the electron beam and therefore the transverse kick has to be minimized. Electromagnetic simulations are applied to investigate different coupler designs and to localize possible problems at an early stage. Cavity external Q and transverse kick can be calculated from 3D electromagnetic eigenmode solutions. The present coaxial-coaxial input couplers at the S-DALINAC are limited to power operation below 500 W under full reflection. Therefore, to reach power operation up to 2 kW two possible new realizations of low-kick waveguide couplers for the S-DALINAC injector are presented, namely a single-waveguide and a twin-waveguide coupler.  
 
TUPKF015 Status of the Superconducting CH-Structure positron, damping, focusing, plasma 991
 
  • H. Podlech, H. Deitinghoff, H. Klein, H. Liebermann, U. Ratzinger, A.C. Sauer, R. Tiede
    IAP, Frankfurt-am-Main
  H-mode cavities (IH-DTL, IH-RFQ, 4-Vane-RFQ) have been developed and operated successfully during the last decades for ion acceleration. At the IAP Frankfurt a new type of H-mode cavity, the CH-structure is under development. This multi cell drift tube cavity is operated in the TE21- mode. Due to its mechanical rigidity, room temperature as well as superconducting versions can be realized. Superconducting CH-structures might be used especially for cw operated linacs in nuclear research facilites and applied research projects like XADS or IFMIF. A superconducting 352 MHz CH-structure (beta=0.1) with 19 gaps will be available for first tests in 2004. We present the status of the cavity and of the new cryo laboratory in Frankfurt.  
 
TUPKF016 Dynamic Lorentz Force Detuning Studies in TESLA Cavities positron, damping, focusing, plasma 994
 
  • V. Ayvazyan, S. Simrock
    DESY, Hamburg
  Dynamic detuning of the superconducting rf cavities due to Lorentz force induced mechanical excitation is a critical concern since the magnitude can approach the cavity bandwidth and require significant additional rf power for field control. In this paper, the influence of high accelerating fields on the resonance frequency in superconducting TESLA cavities is discussed. Cavities at the TESLA Test Facility have been operated at the design operating gradient close to 25 MV/m. It is shown that Lorentz force detuning constant factors are different for different cavities, significant spread have been observed.  
 
TUPLT082 Generation of a Femtosecond Electron Beam for Nanoscience and Nanotechnology septum, sextupole, electron, booster 1348
 
  • J. Yang, T. Kozawa, S. Tagawa, Y. Yoshida
    ISIR, Osaka
  A new S-band femtosecond electron linear accelerator was developed in Osaka University for the study of radiation-induced ultrafast physical and chemical reactions in femtosecond time regions. The femtosecond electron accelerator was constructed with a laser driven photocathode RF gun, a linear accelerator (linac) and a magnetic pulse compressor. The RF gun was driven by a mode-locked Nd:YLF picosecond laser. The electron beam produced by the RF gun was accelerated in the linac with energy modulattion by adjusted the RF phase. The magnetic pulse compression, which was constructed with two 45o-bending magnets and four quadrupole magnets, is a technique to longitudinally focus a charged beam by rotating the phase space distribution in a magnetic field. The picosecond electron pulse, which was generated in the RF gun and accelerated in the linac with energy modulation, was compressed into femtosecond by adjusted the quadrupole magnetic fields. The femtosecond electron pulse is expected for the studies of ultrafast reactions in nano-space.  
 
TUPLT085 J-PARC Construction and its Linac Commissioning septum, sextupole, electron, booster 1351
 
  • Y. Yamazaki
    JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  The J-PARC(Japan Proton Accelerator Research Complex) accelerator is under construction in JAERI Tokai site. The beam commissioning will be started there by the end of 2006. Prior to this, the front end of the linac was beam-commissioned in 2003 at KEK. The negative hydrogen beam with a peak current of 30 mA was accelerated up to 20 MeV by the first tank of three DTL's following the 3-MeV RFQ linac. The 324-MHz DTL contains the electro quadrupole magnets with water-cooling channels specially fabricated by means of electroforming and wire-cutting technologies. The construction status of the J-PARC accelerator is also presented.  
 
TUPLT086 A 40MeV Electron Source with a Photocathode for X-ray Generation through Laser-compton Scattering septum, sextupole, electron, booster 1354
 
  • F. Sakai, N. Nakajyo, Y. Okada, T. Yanagida, M. Yorozu
    SHI, Tokyo
  .3 keV femtosecond X-ray generation through laser-Compton scattering with 14MeV electron source and a TW Ti:sapphire laser was achieved. In order to increase the X-ray energy up to 15 keV for some applications, e.g. protein crystallography, we modified the system to increase electron energy. Electron beams emitted from a S-band RF photocathode are accelerated up to 40MeV with two 1.5m standing-wave linacs. The beams are bended at 90 degree using an achromatic bending system, then focused with a triplet quadrupole-magnet to be interacted with laser pulses. The characteristics of electron beams, emittance, energy and energy dispersion, will be described.  
 
TUPLT087 Deflection Element for S-LSR septum, sextupole, electron, booster 1357
 
  • M. Ikegami, H. Fadil, A. Noda, T. Shirai, M. Tanabe, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • T. Fujimoto, K. Noda, H. Ogawa, S. Shibuya, T. Takeuchi
    NIRS, Chiba-shi
  • M. Grieser
    MPI-K, Heidelberg
  • H. Okamoto
    HU/AdSM, Higashi-Hiroshima
  Main lattice of the ion storage and cooler ring, S-LSR is composed of 6 dipole and 12 quadrupole magnets. The maximum magnetic field, the radius of curvature and gap height are 0.95 T, 1050 mm and 70 mm, respectively. The field measurement of the dipole magnets has been completed with use of Hall-probe position controlled by driving mechanism composed of stepping motors and ball-screws. In order to cancel out the momentum dispersion, the radial electric field is superposed with the magnetic field. The radial electric field is applied by the electrodes installed into the vacuum vessel set inside the rather limited gap of the dipole magnet. Good field quality is to be realized with use of intermediate electrodes. In the present paper, the results of the magnetic field measurements are presented together with the design of the superposed electric field.  
 
TUPLT088 Beam Cooling at S-LSR septum, sextupole, booster, ion 1360
 
  • A. Noda, H. Fadil, S. Fujimoto, M. Ikegami, T. Shirai, M. Tanabe, H. Tongu
    Kyoto ICR, Uji, Kyoto
  • M. Grieser
    MPI-K, Heidelberg
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  • K. Noda, T. Takeuchi
    NIRS, Chiba-shi
  • H. Okamoto, Y. Yuri
    HU/AdSM, Higashi-Hiroshima
  S-LSR is an ion accumulation and cooler ring with the circumference and maximum magnetic rigidity of 22.589 m and 1.0T.m, respectively. Electron beam cooling will be applied for laser-produced hot ion beam after phase rotation. Electron cooler for S-LSR is now under construction and the beam simulation is also going on. Laser cooling of Mg ion with low energy (35 keV) is also planned in 3-dimensional way with use of Synchro-Betatron coupling.so as to realize ultra cold beam. Cancellation of shear force due to orbit-length difference in the dipole section is to be studied with use of overlapping of the radial electric field inversely proportional to the curvature radius with the uniform vertical magnetic field. Possible experiments to approach to ultra-cold beam is also to be studied by computer simulation  
 
TUPLT089 Status of PEFP 3MeV RFQ Development septum, sextupole, booster, ion 1363
 
  • Y.-S. Cho, B.-H. Choi, S.-H. Han, J.-H. Jang, Y.H. Kim, H.-J. Kwon, C.-B. Shim
    KAERI, Daejon
  In the PEFP (Proton Engineering Frontier Project), a 350MHz, 3MeV RFQ (Radio Frequency Quadrupole) has been developed and tested. The tuning results showed that the resonant frequency is somewhat higher than 350MHz and other methods in addition to slug tuners should be used to tune the cavity correctly. To check the cavity characteristics, high power RF test has been done. The required peak RF power is 600kW and pulse width, repetition rate for initial test are 100 micro-s, 10Hz respectively. To solve the problems in PEFP RFQ, the upgrade design of 3MeV RFQ has been decided. The main concept of this upgrade design is constant vane voltage profile with the same length of RFQ. The other parameters (350MHz, 3MeV, 20mA) are the same with the previous RFQ. With constant vane voltage profile, fabrication of RFQ can be easier, and with the same mechanical dimension, other parts such as vacuum pumping station can be re-used. In this paper, the test results of the PEFP RFQ, and the details of beam dynamics design/engineering design of upgrade RFQ will be presented.  
 
TUPLT090 Combined Beam Dynamics Study of the RFQ and DTL for PEFP septum, sextupole, booster, proton 1366
 
  • J.-H. Jang, Y.-S. Cho, H.-J. Kwon
    KAERI, Daejon
  One of the goals of the Proton Engineering Frontier Project (PEFP) is to get 20 MeV proton beams of 20 mA through a 3 MeV RFQ and a 20 MeV DTL. This work is related to the combined beam dynamics study of the low energy proton accelerators in order to test the validity of the connection of the independently designed structures as well as to study the MEBT for beam transportation.  
 
TUPLT091 Fabrication Status of the PEFP 20 MeV DTL septum, sextupole, booster, ion 1369
 
  • M.-Y. Park, Y.-S. Cho, J.-H. Jang, Y.H. Kim, H.-J. Kwon
    KAERI, Daejon
  The PEFP (Proton Engineering Frontier Project) 20 MeV DTL have been constructed in KAERI site. The fabrication of the first tank is finished and the DT installation is in the process. We choose the pool-type electromagnets as the focusing magnet and 50 DTs will be installed on first tank. We tested the winding schemes of copper coils on the iron core and measured the magnetic field saturation.In this paper, the results of the tank fabrication and quadrupole magnet test are presented.  
 
TUPLT092 Optics and Magnet Design for Proton Beam Transport Line at PEFP septum, sextupole, proton, booster 1372
 
  • H.-S. Kang, H.S. Han, S.H. Jeong, Y.G. Jung, D.E. Kim, M. Kim, H.G. Lee, T.-Y. Lee, H.S. Suh
    PAL, Pohang
  The PEFP proton linac is designed to have two proton beam extraction lines at the 20-MeV and 100-MeV end, respectively. Each extraction line has 5 to 6 beamlines for proton beam users. The proton beam transport system for users? experiments will be prepared for this purpose. At the beginning, the beam optics for the proton beam transport system is designed with the TRACE code. The optics should be designed so as to meet the users? various requirements which might be to control the beam size and intensity at the beam target, and the timing of the proton beam. The magnet to distribute the proton beam to many beamlines is an AC magnet which has an AC frequency of 15 Hz, and is powered with a programmable AC power supply. In this paper, the result of the optics design will be presented and the magnet design will be described.  
 
TUPLT093 Tune Survey of Dynamic Apertures for High-brilliance Optics of the Pohang Light Source septum, sextupole, proton, booster 1375
 
  • E.-S. Kim
    PAL, Pohang
  The PLS storage ring is a 2.5 GeV light source and the dynamic apertures in a lattice for the low emittance in the ring have been investigated by a simulation method. The dynamic apertures that include effects of machine errors and insertion devices were obtained by a tune survey in the simulation. It was also shown that how large are the dynamic aperture compensated after corrections of a CODs. The betatron tune for the operation of the high-brilliance lattice are investigated based on the view point of dynamic apertures obtained from a tune survey.  
 
TUPLT095 Precision Field Mapping System for Cyclotron Magnet septum, sextupole, proton, booster 1378
 
  • K.-H. Park, Y.G. Jung, D.E. Kim, L.W.W. Lee
    PAL, Pohang
  • J.-S. Chai, Y.S. Kim
    KIRAMS, Seoul
  • B.-K. Kang, S.H. Shin, M. Yoon
    POSTECH, Pohang
  A 13 MeV cyclotron has been developed by KIRAMS for radio-isotopes production such as F-18 and O-15 for positron emission tomography(PET). To characterize the cyclotron magnet precisely, a Hall probe mapping system with very high precise positioning mechanism in the Cartesian coordinate has been developed. Hall probe assembly was translated in two dimensions by two stepping motors at both sides of the Hall-probe-carrier to keep synchronously rotation sharing one step-pulse source for x-axis and one motor for y-axis. The data acquisition time had reduced to 60 minutes in full mapping by 'flying' mode. The accuracy of the measurement system is better than during the entire mapping process. In this paper the magnetic field measurement system for the cyclotron magnet is described, and measurement results are presented.  
 
TUPLT096 RFQ Low Level RF System for the PEFP 100MeV Proton Linac septum, sextupole, booster, optics 1381
 
  • I.H. Yu, M.-H. Chun, K.M. Ha, Y.J. Han, W.H. Hwang, M.H. Jeong, H.-S. Kang, D.T. Kim, S.-C. Kim, I.-S. Park, J.S. Yang
    PAL, Pohang
  • Y.-S. Cho, K.T. Seol
    KAERI, Daejon
  The 100MeV Proton linear accelerator (Linac) for the PEFP (Proton Engineering Frontier Project) will include a 3MeV, 350MHz RFQ(Radio-Frequency Quadrupole) Linac. The RFQ accelerates a 20mA proton beam from 50keV to 3MeV. The low level RF system for RFQ provides field control. In addition to field control, it provides cavity resonance control. An accelerator electric field stability of ± 1% in amplitude and ± 1° in phase is required for the RF system. The low level RF system has been designed and is now being fabricated.  
 
TUPLT098 Vertical Beam Motion in the AGOR Cyclotron septum, sextupole, booster, optics 1384
 
  • M.A. Hofstee, S. Brandenburg, H. Post, W.K. van Asselt
    KVI, Groningen
  Large-scale vertical excursions have been observed in the AGOR cyclotron for light ionbeams at energies close to the focussing limit (E/A =200 Q/A MeV per nucleon). With increasing radius the beam gradually moves down out of the geometrical median plane by several mm, leading to internal beamlosses. It was concluded that this effect is caused by a vertical alignment error of the coils combined with the weak vertical focussing for the beams concerned. Moving the main coils by a total of 0.37 mm has significantly improved the situation at large radii, but results in internal beamlosses for certain beams at small radii due to a large upward excursion. A systematic study of the vertical beam dynamics as a function of beam particle and energy will be presented. Possible causes and solutions will be discussed.  
 
TUPLT099 A Kicker Pulse Power Supply with Low Jitter septum, sextupole, kicker, booster 1387
 
  • C.-S. Fann, J.-P. Chiou, S.Y. Hsu, K.-B. Liu
    NSRRC, Hsinchu
  The performance of kicker pulse power supplies is the main parameter to increase injection efficiency of storage ring that is an important issue for laboratory of synchrotron radiation research. The output current waveform of a kicker pulse power supply with low timing jitter is our goal for years that must satisfy the Top-Up mode injection requirement of NSRRC. In the past years kicker pulse power supplies of storage ring of NSRRC are immersed in isolation oil to sustain high voltage operational environment that led difficult to maintain, electronic component degrading and uneasy to tune parameters. Air-cooling and air-isolation is adopted in the new design structure for kicker pulse power supply system and an pre-trigger unit MA2709A is installed to trigger thyratron tube CX1536A, a kicker pulse power supply with low timing jitter 1~2ns(p-p) is obtained and could satisfy for Top-Up mode injection and maintenance is more easier than before.  
 
TUPLT102 Field Study of the 4T Superconducting Magnet for Rapid Cycling Heavy Ion Synchrotrons septum, kicker, booster, optics 1390
 
  • V.A. Mikhaylov, P.G. Akishin, A.V. Butenko, A.D. Kovalenko
    JINR, Dubna, Moscow Region
  The problem of the magnetic field optimization of a 4T dipole magnet with circular aperture of 100-110 mm for rapid cycling synchrotron is considered. A single layer low inductance coil made of hollow superconducting high current cable operating at 30 kA is used. The magnetic field ramp rate up to 4 T/s should be achievable. Mathematical method to minimize sextupole and higher order non-linearities to the tolerable values by variation of angular coil turn position is developed. The results of numerical simulation for 2D part magnetic field are presented. The further possibilities to improve the field quality for similar lattice magnets and their application for heavy ion synchrotrons and boosters are discussed.  
 
TUPLT103 Possibilities for Experiments with Rare Radioactive Ions in a Storage Ring Using Individual Injection septum, ion, booster, optics 1393
 
  • A.O. Sidorin, I.N. Meshkov, A.O. Sidorin, A. Smirnov, E. Syresin, G.V. Troubnikov
    JINR, Dubna, Moscow Region
  • T. Katayama
    CNS, Saitama
  • W. Mittig, P. Roussel-Chomaz
    GANIL, Caen
  A radioactive ion beam produced at a target bombarded with a primary beam has after a fragment separator a relatively large emittance and small production rate. For instance, typical flux of 132Sn isotope at the exit of fragment-separator is about 5×105 ions/s. Conventionally used scheme of the ion storage in a ring based on multitutrn injection and (or) RF stacking and stochastic cooling application can not provide a high storage rate at so pure intensity especially for short lived isotopes. In this report we discuss an alternative storage scheme which is oriented to the continuous ion beam from fragment separator at production rate of 104 ions/s or even less. It is based on the fact, that at low production rate the parameters of each particle can be measured individually with rather high accuracy. The particle trajectory can be individually corrected in a transfer channel from fragment separator to the storage ring using system of fast kickers. A fast kicker in the ring synchronized with a circulating bunch provides continuous injection of the ions. The scheme permits to store the ion number required for precise mass measurements and internal target experiment. A hope to obtain large luminosity of ion-electron collisions is related with a possibility of the ion beam crystallization at small particle number.  
 
TUPLT104 Particle Dynamics in the Low Energy Positron Toroidal Accumulator: First Experiments and Results ion, electron, booster, optics 1396
 
  • G.V. Troubnikov, V. Antropov, E. Boltushkin, V. Bykovsky, A.I. Ivanov, S. Ivashkevich, A. Kobets, I.I. Korotaev, V. Lohmatov, I.N. Meshkov, D. Monahov, V. Pavlov, R. Pivin, I.A. Seleznev, A.O. Sidorin, A. Smirnov, E. Syresin, S. Yakovenko
    JINR, Dubna, Moscow Region
  The project of Low Energy Particle Toroidal Accumulator (LEPTA) is dedicated to construction of a positron storage ring with electron cooling of positrons circulating in the ring. Such a peculiarity of the LEPTA enables it automatically to be a generator of positronium (Ps) atoms, which appear in recombination of positrons with cooling electrons inside the cooling section of the ring. The project has a few goals: to study electron and positron dynamics in the ring (particle motion in the horizontal and vertical planes are coupled contrary to of classic cycle accelerators), to set up first experiments with Ps in flight; Magnetic measurements of main LEPTA elements are performed. Several elements : kicker, injection system of electron beam, helical quadrupole, septum magnet are tested and expected design parameters were achieved for those elements. The investigations of electron beam dynamics are started. First results of experiments with circulating electron beam are presented and discussed in this article. Several beam diagnostic methods for studying of strong coupled motion of charged particles are proposed and tested.  
 
TUPLT105 Measurement of Activation Induced by an Argon Beam in a Copper Target at the SIS18 ion, electron, booster, optics 1399
 
  • A. Fertman, A. Golubev, M. Prokuronov, B.Y. Sharkov
    ITEP, Moscow
  • G. Fehrenbacher, R.W. Hasse, I. Hofmann, E. Mustafin, D. Schardt, K. Weyrich
    GSI, Darmstadt
  Results of the measurement of activation induced by Argon beam with energies of E=100,200,800 MeV/u in the copper target are presented. The densities of various radioactive isotopes are derived from the measurements. Long-time prediction of radioactivity and accumulated doses in the accelerator equipment is calculated.  
 
TUPLT106 New Developments of a Laser Ion Source for Ion Synchrotrons electron, booster, optics, proton 1402
 
  • S. Kondrashev, A. Balabaev, K. Konukov, B.Y. Sharkov, A. Shumshurov
    ITEP, Moscow
  • O. Camut, J. Chamings, H. Kugler, R. Scrivens
    CERN, Geneva
  • A. Charushin, K. Makarov, Y. Satov, Y. Smakovskii
    SRC RF TRINITI, Moscow region
  Laser Ion Sources (LIS) are well suited to filling synchrotron rings with highly charged ions of almost any element in a single turn injection mode. We report the first measurements of the LIS output parameters for Pb27+ ions generated by the new 100 J/1 Hz Master Oscillator - Power Amplifier CO2-laser system. A new LIS has been designed, built and tested at CERN, as an ion source for ITEP-TWAC accelerator/accumulator facility, and as a possible future source for an upgrade of the Large Hadron Collider (LHC) injector chain. The use of the LIS based on 100 J/1 Hz CO2-laser together with the new ion LINAC, as injector for ITEP-TWAC project is discussed.  
 
TUPLT111 RF Focusing of Low-Charge-to-Mass-Ratio Heavy-Ions in a Superconducting Linac electron, focusing, linac, 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, linac, 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, linac, 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, linac, 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, linac, 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, linac, 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, linac, 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, linac, 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, linac, 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, linac, 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 linac, 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.  
 
THPKF058 Experimental Experience with a Thermionic RF-gun target, cathode, laser, beamlosses 2391
 
  • S. Werin, Å. Andersson, M. Bergqvist, M. Brandin, L. Malmgren, S. Werin
    MAX-lab, Lund
  • G. Georgsson
    Danfysik A/S, Jyllinge
  An RF-gun structure developed at MAX-lab, and thus different from the most common BNL-structure, is in operation as a thermionic RF-gun at MAX-lab. The properties of the gun have been investigated. Especially aspects such as extractable energy range, emittance properties at various beamloading conditions and extracted current.  
 
THPKF059 Adaption of an RF-gun from Thermionic to Photo Cathode target, beamlosses, linac, 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.  
 
THPKF060 Singapore Synchrotron Light Source– Helios 2 and Beyond target, beamlosses, laser, brilliance 2397
 
  • H.O. Moser, B.D.F. Casse, E.P. Chew, M. Cholewa, C. Diao, S.X.D. Ding, M. Hua, J.R. Kong, Z. Li, S.bin. Mahmood, M.L. Ng, B.T. Saw, S.V.S. Vidyaraj, O. Wilhelmi, J.H.W. Wong, P. Yang, X.J. Yu
    SSLS, Singapore
  SSLS is operating a superconducting 700 MeV electron storage ring to produce synchrotron radiation over a useful spectral range from 10 keV to the far infrared for micro/nanofabrication, phase contrast imaging, surface and nano science with soft X-rays, and hard X-ray diffraction and absorption spectroscopy. An Infrared spectro/microscopy beamline is under construction. Latest results from all beamlines will be presented. SSLS is also working on a conceptual study of a Linac Undulator Light Installation (LIULI) that includes a superconducting miniundulator. Pursuing earlier work* a prototype built by ACCEL is being tested at SSLS and will later serve for FEL studies in cooperation with SSRF at Shanghai.

* A. Geisler, A. Hobl, D. Krischel, H.O. Moser, R. Rossmanith, M. Schillo, First Field Measurements and Performance Tests of a Superconductive Undulator for Light Sources with a Period Length of 14 mm, ASC Conference, Houston, TX, August 2002

 
 
THPKF061 RT-office for Electron Beam, X-ray, and Gamma-ray Dosimetry target, radiation, beamlosses, laser 2400
 
  • G.F. Popov, V.T. Lazurik, V.M. Lazurik, Y.V. Rogov
    KhNU, Kharkov
  An absorbed dose of electron beam (EB),X-ray (bremsstrahlung), and gamma-ray within the irradiated product is one of the most important characteristic for all industrial radiation-technological processes. The conception for design of the Radiation-Technological Office (RT-Office) - software tools for EB, X-ray, and gamma-ray dosimetry for industrial radiation technologies was developed by authors. RT-Office realize computer technologies at all basic stages of works execution on the RTL using irradiators of EB, X-ray, and gamma-ray in the energy range from 0.1 to 25 MeV. The specialized programs for simulation of EB, X-ray, and gamma-ray processing and for decision of special tasks in dosimetry of various radiation technologies were designed on basis of the RT-Office modules. The use of the developed programs as predictive tools for EB,X-ray, and gamma-ray dose mapping, for optimization of regimes irradiation to receive minimum for dose uniformity ratio, for reducing the volume of routine dosimetry measurements of an absorbed dose within materials at realization of the radiation-technological processes are discussed in the paper.  
 
THPKF062 Comparison of Dose Distribution Prediction in Targets Irradiated by Electron Beams with Dosimetry target, simulation, beamlosses, laser 2403
 
  • G.F. Popov, V.T. Lazurik, V.M. Lazurik, Y.V. Rogov
    KhNU, Kharkov
  • I. Kalushka, Z. Zimek
    Institute of Nuclear Chemistry and Technology, Warsaw
  The features of the absorbed depth-dose distribution (DDD) on boundaries of two contacting materials and material with air irradiated with an electron beam (EB) were predicted by simulation with the software ModeRTL (Modeling of the radiation-technological lines (RTL)). Validation of DDD prediction with dosimetry was fulfilled on the industrial RTL with linear electron accelerator LAE 13/9 at the INCT, Warsaw. Simulation and measurement of boundary effects of DDD were carried out for targets irradiated by scanning EB with energy 10 MeV on moving conveyer. The irradiated materials were represented as parallelepipeds with all sizes greater than range of electrons in material. Cellulose Triacetate (CTA) dosimetric film (FTR-125) in form of strips inserted between materials and air in parallel with an axis of EB was used for dosimetry. Such irradiation setup allows to receive the complete curve of DDD on the boundary of contacting materials by one dosimetric film. The physical regularities for DDD on the boundary of contacting materials predicted by simulation methods were experimentally confirmed. Investigation of those anomalies is necessary in practice to estimate the quality of an irradiation performed on RTL at realization of various industrial EB processing.  
 
THPKF063 Parameters of X-ray Radiation Emitted by Compton Sources target, simulation, beamlosses, brilliance 2406
 
  • E.V. Bulyak, V. Skomorokhov
    NSC/KIPT, Kharkov
  Presented are results of analytical study on X–ray beam parameters generated in the Compton storage rings. A model with the given circulating electron bunch parameters and the laser splash as well is considered. For this model, the total yield of x–ray quanta is derived as a function of the crossing angle and geometric dimensions of both the bunch and splash. Also spectral characteristics of emitting x–ray beam are evaluated with account for the collimating conditions and both the angular and energy spreads in the bunch. As is shown the width of x–ray energy spectrum is narrowest for the x-ray beam collimated along the bunch orbit. With increasing the scattering angle (with respect to the bunch orbit) the spectrum of emitting quanta is widening. Problems of x-ray beam generation with required energy and brightness with the Compton storage rings are discussed.  
 
THPKF064 Status of Kharkov X-ray Generator based on Compton Scattering NESTOR target, vacuum, simulation, beamlosses 2409
 
  • A.Y. Zelinsky, V.P. Androsov, E.V. Bulyak, I.V. Drebot, P. Gladkikh, V.A. Grevtsev, V.A. Ivashchenko, I.M. Karnaukhov, V. Lapshin, V. Markov, N.I. Mocheshnikov, A. Mytsykov, F.A. Peev, A.V. Rezaev, A.A. Shcherbakov, V.L. Skirda, V.A. Skomorokhov, Y.N. Telegin, V.I. Trotsenko
    NSC/KIPT, Kharkov
  • A. Agafonov, A.N. Lebedev
    LPI, Moscow
  • J.I.M. Botman
    TUE, Eindhoven
  • T.R. Tatchyn
    SLAC/SSRL, Menlo Park, California
  Nowadays the sources of the X-rays based on a storage ring with low beam energy and Compton scattering of intense laser beam are under development in several laboratories. In the paper the state-of-art in development and construction of cooperative project of a Kharkov advanced X-ray source NESTOR based on electron storage ring with beam energy 43 - 225 MeV and Nd:YAG laser is described. The layout of the facility is presented and main results and constructing timetable are described. The designed lattice includes 4 dipole magnets with combined focusing functions, 20 quadrupole magnets and 19 sextupoles with octupole component of magnetic field. At the present time a set of quadrupole magnet is under manufacturing and bending magnet reconstruction is going on. The main parameters of developed vacuum system providing residual gas pressure in the storage ring vacuum chamber up to 10-9 torr are presented along with testing measurement at NSC KIPT vacuum bench. The facility is going to be in operation in the middle of 2006 and generated X-rays flux is expexted to be of about 1013 phot/s.  
 
THPKF066 Conception of X-ray Source Based on Compact Wakefield Undulator target, vacuum, simulation, undulator 2412
 
  • A. Opanasenko
    NSC/KIPT, Kharkov
  Study of interaction of bunched charged ultrarelativistic particles with own wakefields in periodic rf structures detects new applications in the area of accelerator physics and technology. Conception of monochromatic X-ray source based on wakefield undulator, WFU, with very short period is presented. In the base of photon generation by the WFU lies a new mechanism of undulator-type radiation emitted by an ultrarelativistic electron bunch that undulates due to non-synchronous spatial harmonics of its wakefields while the bunch moves along a periodic waveguide. The features of the hard radiation and yield of photons depending on waveguide sizes and charge distribution are considered. The creation of the WFU with sub-millimetre periods due to advanced accelerator technology, such as deep X-ray lithography, opens possibilities to obtain high brightness X-rays at employing comparatively low electron energies without external alternative fields. That can have commercial significance for technological and medical applications.  
 
THPKF067 Progress of the DIAMOND Storage Ring and Injector Design. target, vacuum, simulation, undulator 2415
 
  • S.L. Smith, D.J. Holder, J.K. Jones, J.A. Varley, N.G. Wyles
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  • R. Bartolini, I.P.S. Martin, B. Singh
    Diamond, Oxfordshire
  DIAMOND is a state of the art 3 GeV synchrotron light source that will be available to users in 2007. Considerable further progress has been made on the accelerator physics design of the storage ring, booster and other associated injector systems. Detailed analysis of injection processes, lifetime, coupling, instabilities, feedback systems and dynamic aperture have been undertaken driven by the procurement activity and the desire to fully understand all aspects of the accelerator's performance.  
 
THPKF068 An Advanced Light Source Proposed for the South Eastern USA target, lattice, vacuum, emittance 2418
 
  • V.P. Suller, M.G. Fedurin, J. Hormes
    LSU/CAMD, Baton Rouge, Louisiana
  • D. Einfeld
    CELLS, Bellaterra (Cerdanyola del Vallès)
  • G. Vignola
    SESAME, Amman
  At this time CAMD, a 1.3 GeV second generation storage ring, is the only synchrotron radiation facility in the Southeastern USA. To cater for the increasing demand for synchrotron light in this region a study is being made for a new high performance source. In keeping with its role as a regional source, it must be economical to construct and operate yet provide high brightness beams from its Insertion Devices. These will need to span both the soft X-ray region (1-2 keV) and the X-ray region up to at least 13 keV. A high brightness 3rd generation source is described which exhibits a beam emittance less than 10 nm rads at an energy of 2.5 GeV. By using a lattice cell derived from the Theoretical Minimum Emittance type, this performance is achieved in a circumference of only approximately 160 m. The economical, yet flexible, lattice uses vertically focusing gradient in the dipoles. The lattice functions and other parameters are presented of both a 12 cell double bend design and a 10 cell triple bend. The 12 cell gives a horizontal emittance of 8.5 nm rads and the 10 cell 4.6 nm rads. The dynamical stability of both lattices is described together with the beam performance from the anticipated insertion devices. The current status of the proposal is explained.  
 
THPKF069 Improvements to, and Current Status of, the CAMD Light Source target, lattice, vacuum, emittance 2421
 
  • V.P. Suller, M.G. Fedurin, P. Jines, D.J. Launey, T.A. Miller, Y. Wang
    LSU/CAMD, Baton Rouge, Louisiana
  Throughout 2003 a sustained program of modifications and improvements has been applied to the CAMD light source. These affected the 7 Tesla wiggler, the RF system, the magnet power supplies, the control system, the diagnostics and the injector linac. These modifications and their impact on the storage ring performance are described, together with an analysis of where future improvements should be directed. The present performance and limitations of CAMD are described.  
 
THPKF070 A Beam Based Alignment System at the CAMD Light Source target, vacuum, emittance, simulation 2424
 
  • V.P. Suller, E.J. Anzalone, A.J. Crappell, M.G. Fedurin, T.A. Miller
    LSU/CAMD, Baton Rouge, Louisiana
  Beam based alignment is being applied to the CAMD light source. It is implemented by a flexible and versatile system of electronic shunts which are applied to each of the storage ring lattice quadrupoles. The essential design features of the electronic shunts are described as is the routine operation of the full system. The improvement to the corrected closed orbit from using the system is shown. Preliminary results are presented of the use of the shunts for correcting the lattice functions.  
 
THPKF071 Linear Coupling and Lifetime Issues in the DIAMOND Storage Ring target, vacuum, coupling, simulation 2427
 
  • R. Bartolini
    Diamond, Oxfordshire
  • N.G. Wyles
    CCLRC/DL/ASTeC, Daresbury, Warrington, Cheshire
  In synchrotron light sources the correction of the linear coupling is an important issue related to the brightness of the photon beam and to the beam lifetime. The vertical emittance of the electron beam in the DIAMOND storage ring will be controlled using 168 skew quadrupoles embedded in the sextupoles of the ring. In this paper we report the linear coupling estimates for the expected misalignment errors and we compare the results of coupling correction with different correction strategies. The effect on lifetimes is also discussed.  
 
THPKF072 Progress with the Diamond Light Source coupling, simulation, insertion, target 2430
 
  • R.P. Walker
    Diamond, Oxfordshire
  Construction of Diamond, the UK?s new 3 GeV, 3rd generation synchrotron light source, is well underway and progressing in-line with the original target of starting storage ring commissioning in January 2006 and being operational for users in January 2007. Having completed the foundations, the main building works are now proceeding at their maximum rate. Most of the major machine components are also under construction, aiming towards the key target date of starting machine installation in September 2004. As well as reporting on the overall status, detailed design developments and component choices will be summarised. The results of tests of various prototype components, including magnets, vacuum vessels and girders, will also be presented.  
 
THPKF073 CIRCE, the Coherent InfraRed CEnter at the ALS coupling, simulation, insertion, target 2433
 
  • J.M. Byrd, S. De Santis, J.-Y. Jung, M.C. Martin, W.R. McKinney, D.V. Munson, H. Nishimura, D. Robin, F. Sannibale, R.D. Schlueter, M. Venturini, W. Wan, M.S. Zolotorev
    LBNL, Berkeley, California
  CIRCE (Coherent InfraRed Center) is a new electron storage ring to be built at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL). The ring design is optimized for the generation of coherent synchrotron radiation (CSR) in the terahertz frequency range. CIRCE operation includes three possible modes: ultra stable CSR, femtosecond laser slicing CSR and broadband SASE. CSR will allow CIRCE to produce an extremely high flux in the terahertz frequency region. The many orders of magnitude increase in the intensity is the basis of our project and enables new kinds of science. The characteristics of CIRCE and of the different modes of operation are described in this paper.  
 
THPLT018 Electron Beam Dynamics Simulations for the Low Emittance Gun feedback, antiproton, electron, target 2502
 
  • M. Dehler, S.C. Leemann
    PSI, Villigen
  • A.E. Candel
    ETH, Zürich
  We report on theoretical simulation performed for the development of a high brightness, field emitter based electron gun suitable for an Angstrom wavelength free electron laser\cite{LEG}. First simulations have been done with available codes in 2 1/2D and 3D for basic gun configurations showing the global and local (due to the granularity of the emitter array) effects on the emittance dilution.Design and construction started on a test setup consisting of a 100 keV electron gun with solenoidal focusing and a diagnostics module. In addition to solenoid focussing, anode shaping will be investigated in order to compensate for non-linear fields leading to space charge blow-up. For advanced simulations of field emitter based guns allowing to resolve individual emitters and to capture the influence of mechanical imperfections, a massive parallel code for 3D particle-in-cell simulations is in development. The electromagnetic field solver is fully functional and the particle tracker has been completed in its basic structures.  
 
THPLT019 Commissioning Results of the Multi Bunch Feedback System at SLS antiproton, electron, target, lattice 2505
 
  • M. Dehler, R. Kramert, P. Pollet, T. Schilcher
    PSI, Villigen
  • D. Bulfone, M. Lonza
    ELETTRA, Basovizza, Trieste
  Within the frame of the project for a multi bunch feedback system for the Swiss Light Source (SLS), a new family of 500 MS/s analog to digital and digital to analog conversion boards with an 8 bit resolution has been developed, containing on board MUX and DEMUX circuitry to reduce data rates to approximately 20 MS/s using up to ten Front Panel Data Port (FPDP) ports. Using six quad processor DSP boards, full bandwidth bunch by bunch feedbacks in the transverse and longitudinal planes are set up to provide bunch by bunch correction kicks with a 2 nsec resolution. We report on the hardware setup and properties as well as feedback performance in the SLS storage ring.  
 
THPLT020 The DSP-based Betatron Tune Feedback of the Ramped 1.5 GeV Electron Storage Ring BoDo antiproton, feedback, electron, target 2508
 
  • B. Keil
    PSI, Villigen
  • K. Wille
    DELTA, Dortmund
  The ramped storage ring BoDo is the full energy injector of the 1.5 GeV synchrotron light source DELTA. All ramped booster magnet power supplies, RF power and beam diagnostics of BoDo are handled by a distributed VME-based DSP (digital signal processor) multiprocessing system developed at DELTA. The VME DSP boards of this system are interconnected by DeltaNet, a novel reflective memory ring network. DeltaNet transmits the measurement data from each DSP board to all other boards in real-time via fibre optic links. The generic hardware and software architecture of the system allows the implementation of different kinds of global real-time feedbacks with correction rates in the range from some 100 Hz to some 10 kHz. This paper presents architecture and performance of a real-time betatron tune feedback that was implemented with the DSP system. The betatron tune is measured and corrected in both planes at a rate of typically 700 Hz for arbitrary beam optics and energy ramps of BoDo. In combination with the global Bodo orbit feedback, the tune feedback increases the performance of Bodo both as an injector and as a testbed for machine studies and newly developed accelerator components.  
 
THPLT021 A DSP-Based Fast Orbit Feedback System for the Synchrotron Light Source DELTA antiproton, feedback, electron, target 2511
 
  • B. Keil
    PSI, Villigen
  • K. Wille
    DELTA, Dortmund
  A DSP-based Fast Orbit Feedback (FOFB) system has been designed for the synchrotron light facility DELTA. DELTA consists of a 60 MeV linac, the ramped storage ring BoDo as full-energy injector and the 1.5 GeV storage ring Delta. BoDo and Delta have the same dipole, quadrupole and corrector magnet design, the same beam pipe design and the same BPM RF frontends, therefore BoDo was used as a testbed for the newly developed FOFB hardware and software. Using the fast corrector magnet power supplies of BoDo, the FOFB could damp orbit perturbations up to 90 Hz. The envisaged future use of the FOFB for the Delta storage ring will require either the partial or full replacement of the present slow (1 Hz bandwidth) Delta corrector power supplies, or additional fast power supplies with dedicated FOFB corrector magnets. A first test of the FOFB in Delta for local orbit stabilization at one beamline is in preparation. This paper presents the results of a successful test of the FOFB at BoDo, where it achieves a correction rate of 4 kHz for a global SVD-based feedback in both planes. The FOFB is based on the "DeltaDSP" VMEbus DSP boards that are also used for the BoDo betatron tune feedback.  
 
THPLT022 The Generic VME PMC Carrier Board: A Common Digital Hardware Platform for Beam Diagnostics and Feedbacks at PSI antiproton, target, lattice, undulator 2514
 
  • B. Keil, C. Buehler, P.-A. Duperrex, U. Greuter, R. Kramert, P. Pollet, V. Schlott, N. Schlumpf, P. Spuhler
    PSI, Villigen
  Rapid progress in digital electronics allows digitization of monitor signals at a very early stage of the signal processing chain, providing optimum performance and maximum flexibility for today's accelerator instrumentation. While the analog front-ends of such systems are usually specific for each monitor type, the subsequent digital part of the processing chain can be unified for many different measurement tasks. The "VME generic PMC Carrier board" (VPC) was developed to achieve this unification at the PSI electron and proton accelerator diagnostics and fast data acquisition and feedback systems. The core of the VME64x board consists of two Virtex2Pro FPGAs with two PowerPCs each, a floating point DSP and RAM. The FPGAs can acquire and process measurement data from the VMEbus P0/P2 connectors or from two application-dependent PMC mezzanine modules. Two 2 GBaud fibre optics transceivers may also be used to aquire or distribute measurement data. Envisaged applications include digital beam position (DBPM) and current monitors for proton beams, data processing for a muon decay experiment, and general beam diagnostics as well as global feedbacks at SLS accelerators and beamlines.  
 
THPLT023 The Use of Photon Monitors at the Swiss Light Source antiproton, photon, target, lattice 2517
 
  • J. Krempasky, M. Böge, T. Schilcher, V. Schlott, T. Schmidt
    PSI, Villigen
  The photon beam position monitors (PBPM) in a synchrotron radiation facility are important tools for beam-line and machine diagnostics since they deliver position and angle information directly from the radiation source point. In the last two years a number of PBPMs have been installed and commissioned at the Swiss Light Source (SLS). Their readouts have been systematically studied and the results have been correlated with data from the digital beam position monitor (DBPM) system. It turns out that the PBPMs help understanding the influence of insertion device gap changes on photon beam position and thus on photon flux and/or energy resolution near the beam-line experimental stations. In addition to the global fast orbit feedback (FOFB), a local slow feedback based on PBPM data has been implemented to remove the remaining systematic effects of the DBPM system and to stabilize the photon beam to a micron level at the experimental station.  
 
THPLT024 Commissioning and Operation of the SLS Fast Orbit Feedback antiproton, photon, target, lattice 2520
 
  • T. Schilcher, M. Böge, B. Keil, P. Pollet, V. Schlott
    PSI, Villigen
  The SLS Fast Orbit Feedback (FOFB) was successfully commissioned in 2003. Since November 2003 it runs during user operation of the accelerator. Taking into account 72 Digital Beam Position Monitors (DBPMs), the FOFB applies SVD-based global orbit corrections for 72 horizontal (x) and 72 vertical (y) correctors at a rate of 4 kHz, compared to ~0.5 Hz for the Slow Orbit Feedback (SOFB) that was used so far. While the SOFB was important for the elimination of orbit drifts due to temperature changes and slowly moving insertion device (ID) gaps, the FOFB is also able to damp orbit oscillations that are caused by fast changes of ID gaps or magnets, by ground and girder vibrations, 3 Hz booster crosstalk and power supply noise. This report presents experience from commissioning and user operation of the FOFB.  
 
THPLT025 Using Visible Synchrotron Radiation at the SLS Diagnostics Beamline antiproton, target, lattice, undulator 2523
 
  • V. Schlott, M. Dach, Ch. David, B. Kalantari, M. Pedrozzi, A. Streun
    PSI, Villigen
  A diagnostics beamline has been set-up at the BX05 bending magnet of the SLS storage ring. It is equipped with a standard bending magnet front end, including two photon beam position monitors (PBPM) for determination of photon beam angle and position as well as a pinhole array monitor for online monitoring of beam size. The visual part of the dipole radiation is transported to an optical lab, where the temporal profile of the storage ring bunches can be measured with a minimal time resolution of 2 ps using a dual sweep, synchrocan streak camera. Simultaneously, beam size and coupling can be measured at 1.8 keV radiation energy with a zome plate monitor overcoming diffraction limitations. This paper describes the beamline design and summarizes the first experimental results.  
 
THPLT026 Beam Profile Measurements at PETRA with the Laserwire Compton Scattering Monitor antiproton, positron, laser, target 2526
 
  • T.  Kamps
    BESSY GmbH, Berlin
  • K. Balewski, H.-C. Lewin, S. Schreiber, K. Wittenburg
    DESY, Hamburg
  • G.A. Blair, G. Boorman, J. Carter, F. Poirier
    Royal Holloway, University of London, Surrey
  • S.T. Boogert
    UCL, London
  • T. Lefevre
    CERN, Geneva
  The vertical beam profile at the PETRA positron storage ring has been measured using a laserwire scanner. A laserwire monitor is a device which can measure high brilliant beam profiles by scanning a finely focused laser beam non-invasively across the charged particle beam. Evaluation of the Compton scattered photon flux as a function of the laser beam position yields the transverse beam profile. The aim of the experiment at PETRA is to obtain the profile of the positron beam at several GeV energy and several nC bunch charge. Key elements of laserwire systems are currently being studied and are described in this paper such as laser beam optics, a fast scanning system and a photon calorimeter. Results are presented from positron beam profile scans using orbit bumps and a fast scanning scheme.  
 
THPLT027 Optical Transition Radiation Based Beam Diagnostics at the BESSY Synchrotron Radiation Source and FEL Accelerators antiproton, positron, target, lattice 2529
 
  • T.  Kamps, K. Holldack, P. Kuske
    BESSY GmbH, Berlin
  Optical Transition Radiation (OTR) based diagnostics tools are widely used in linear accelerators to measure beam parameters like transverse beam size and emittance. Design ideas for OTR stations in the linac section of the BESSY FEL facility are presented. Several key components will be tested in the transfer lines of the BESSY storage ring. Furthermore a novel type of OTR monitor is introduced which enables the measurement of the transverse overlap of seed laser and electron beam in the undulator sections of the linac based FEL facility. Here a special radiator screen will be used allowing simultaneous imaging of both beams in the same optical readout channel.  
 
THPLT028 High Precision Cavity Beam Position Monitor antiproton, positron, target, lattice 2532
 
  • A. Liapine, H. Henke
    TET, Berlin
  A cavity beam position monitor is proposed for measuring the beam deflection in the TESLA energy spectrometer. The precision of the measurement has to be better than 1 micrometer. A slotted cavity is chosen as pick-up in order to reject the background signals and enhance the precision and the dynamic range of the monitor. The paper gives the design overview for two prototypes with operating frequencies of 1.5 GHz and 5.5 GHz, respectively. The results obtained on the test bench with direct conversion electronics are presented. A resolution of about 100 nm was achieved.  
 
THPLT029 Parallel Particle in Cell Computations with GdfidL antiproton, positron, target, lattice 2535
 
  • W. Bruns
    WBFB, Berlin
  The electromagnetic field solver GdfidL has been extended to compute with free moving charges. For computing in parallel, GdfidL partitions the computational volume in many small subvolumes. Each processor computes the electromagnetic field in its part of the whole volume. In addition to the normal field update equations, the movement of the particles must be computed from the Lorentz-force, and the convection current due to the moving charges must be computed and be used to change the electric field near the particle. For each particle, these computations are performed by the processor which is responsible for the volume where the particle is in. Details of the parallel implementation of the used algorithm, Particle in Cell, are given.  
 
THPLT030 A Novel Device for Non-intersecting Bunch Shape Measurement at the High Current GSI-Linac antiproton, positron, target, lattice 2538
 
  • P. Forck, C. Dorn, M.H. Herty, P. Strehl
    GSI, Darmstadt
  • V. Peplov
    RAS/INR, Moscow
  • S. Sharamentov
    ANL, Argonne, Illinois
  Due to the high current of heavy ions accelerated at the UNILAC at GSI, non-intersecting beam diagnostics are mandatory. For bunch length and bunch structure determination in the range of 0.3 to 5 ns a novel device has been realized. It uses the time spectrum of secondary electrons created by atomic collisions between beam ions and residual gas molecules. These electrons are accelerated by an electric field of 400 V/mm toward an electro-static energy analyzer. The analyzer is used to restrict of the effective source region. Then the electrons are deflected by an rf-resonator running in phase with the acceleration frequency (36 or 108 MHz) to transform the time spectrum into spatial separation. The detection is done with a multi-channel plate equipped with a phosphor screen and observed by a digital CCD camera. The achieved time resolution is at least 50 ps, corresponding to 2 degree of rf frequency. The general layout of the device and first results will be presented.  
 
THPLT031 Comparison of Rate Equation Models for Equilibrium Beam Parameters antiproton, positron, lattice, wiggler 2541
 
  • R.W. Hasse, O. Boine-Frankenheim
    GSI, Darmstadt
  We calculate equilibrium beam parameters from the counteraction of intrabeam scattering (IBS), electron cooling (EC) and target interaction for typical beams in the GSI cooler storge ring ESR and in the proposed HESR. This work is complementary to kinetic modeling efforts at GSI. We developed an easy to use simulation tool that includes various models for the EC rates and the IBS rates, averaged of the detailed ring lattices. The obtained scaling of the equilibrium parameters with beam current and energy are compared with existing experimental data from the ESR and with kinetic simulation results for the HESR.  
 
THPLT032 Computer Controlled Beam Diagnostics for the HICAT Facility antiproton, positron, lattice, wiggler 2544
 
  • M. Schwickert, A. Peters
    GSI, Darmstadt
  A set of 93 diagnostic devices for beam diagnostics in the heavy ion cancer therapy facility (HICAT) at the university hospital in Heidelberg is currently under development at GSI. For the HICAT facility that is presently under construction, all beam diagnostic devices are fully computer controlled and allow an automated detection of all relevant beam parameters. The HICAT rasterscan method with active variation of intensity, energy and beam size requires the exact knowledge of the time resolved and spatial structure of the ion beam. An overview of the integrated devices is presented and the intensity measurement of both, the DC and AC beam in the different parts of the accelerator facility are reviewed. Additionally, the timing and control of the diagnostic devices are described.  
 
THPLT033 The Heavy Ion Gantry of the HICAT-facility antiproton, ion, positron, lattice 2547
 
  • U. Weinrich, R. Fuchs
    GSI, Darmstadt
  • P. Emde
    MAN Technologie AG, Mainz
  The Heavy Ion Cancer Therapy Project HICAT at the University Hospital of Heidelberg is under construction. One unique feature of the treatment facility is the first heavy ion gantry in the world. The Gantry will allow the patient treatment with different ion species up to 430 MeV/u with full geometrical flexibility. This functionality has to be maintained for up to 300 000 rotations over the envisaged life cycle of 15 years. GSI has taken the responsibility to coordinate the design and construction of all the different required components. At the time of the conference the design will be finished and the construction started. The contribution will report on challenging construction items like the survey and alignment strategy, safety aspects, flexibility of the ion optics. In order to gain confidence on the principle a test bench with the last part of the gantry was already mounted in a fixed manner at GSI and beam measurements were performed. The results of these tests will also be reported.  
 
THPLT034 Implementation of Higher Order Moments for Beam Dynamics Simulation with the V-Code antiproton, ion, positron, lattice 2550
 
  • W. Ackermann, T. Weiland
    TEMF, Darmstadt
  Based on the moment approach V-Code is implemented to simulate charged particle beam dynamics in linear accelerators. Its main aim is to perform elementary studies in those cases when the beam can be considered as a whole and thus making the motion of individual particles negligible in the overall view. Therefore an ensemble of particles can be well described by the moments of its phase-space distribution and the regarded order influences naturally the achievable accuracy as well as the computational effort. Since the well known moment equations generally are not closed, a technique to limit the number of involved moments has to be applied. So far all moments up to the second order have been considered whereas higher order moments are truncated. As a further step towards higher accuracy the influence of higher order moments has to be investigated. For this reason additional third-order equations are implemented into the V-Code and the achieved results are compared with previous second-order-based ones as well as with higher order approximations.  
 
THPLT061 Development of a Multibunch Photo-cathode RF Gun System vacuum, antiproton, emittance, cathode 2625
 
  • J. Urakawa, M. Akemoto, S. Araki, H. Hayano, M. Kuriki, T. Muto, N. Terunuma, Y. Yamazaki
    KEK, Ibaraki
  • M.K. Fukuda, K. Hirano, M. Nomura, M. Takano
    NIRS, Chiba-shi
  A multibunch photo-cathode RF gun system has been developed as a electron source for the production of quasi-monoenergetic X-rays based on inverse Compton scattering. This system consists of a photocathode rf gun, a cathode system, a laser system, beam diagnostic sections, and beam dump line. The gun produces 100 bunches with a 2.8ns bunch spacing and 5nC bunch charge. We will report on the RF gun system with 4 bending dipoles of a chicane which makes the laser injection to the cathode with perpendicular angle possible.  
 
THPLT062 Alternating-phase-focused Linac for an Injector of Medical Synchrotrons vacuum, antiproton, linac, 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.  
 
THPLT063 Proposal of Carbon-beam Facility for Cancer Therapy in Japan vacuum, antiproton, emittance, cathode 2631
 
  • K. Noda, T. Fujisawa, T. Furukawa, Y. Iwata, T. Kanai, M. Kanazawa, N. Kanematsu, A. Kitagawa, Y. Kobayashi, M. Komori, S. Minohara, T. Murakami, M. Muramatsu, S. Sato, Y. Sato, S. Shibuya, E. Takada, O. Takahashi, M. Torikoshi, E. Urakabe, S. Yamada, K. Yoshida
    NIRS, Chiba-shi
  Since 1994, the clinical trial at HIMAC has been successfully being progressed and more than 1,700 patients have treated with carbon ions. Owing to the good result of HIMAC, several medical groups in Japan have strongly required the carbon therapy facility. Based on the development of accelerator and the irradiation technologies for 10 years, therefore, we started to design a carbon therapy facility in Japan. The accelerator complex for the facility consists of two ECR ion sources with permanent magnets, an injector linac cascade (RFQ+IH) with the energy of 4 MeV/n, a synchrotron ring with the maximum energy of 400 MeV/n and beam delivery system for three treatment rooms. The R&D for the new facility has been already approved and will be started from April 2004. We will describe the conceptual design of the new facility.  
 
THPLT064 Enhancement of Laser Power from a Mode Lock Laser with an Optical Cavity laser, vacuum, antiproton, emittance 2634
 
  • M. Nomura, K. Hirano, M. Takano
    NIRS, Chiba-shi
  • S. Araki, Y. Higashi, T. Taniguchi, J. Urakawa, Y. Yamazaki
    KEK, Ibaraki
  • Y. Honda, N. Sasao, K. Takezawa
    Kyoto University, Kyoto
  • H. Sakai
    ISSP/SRL, Chiba
  We have developed a laser-wire beam monitor to measure a beam profile in the KEK/ATF damping ring. This monitor is based on the inverse Compton scattering with a thin wire of the laser. The laser-wire is produced with a Fabry-Perot optical cavity in which laser power from a CW laser is stored and enhanced up to 1000 times. We have a plan to increase a gamma ray flux by using a pulsed laser instead of the CW laser. There are many applications for such a high flux gamma ray, e.g. medical use, transmutation and so on. We have done a test experiment of laser pulse stacking with a mode lock laser where wavelength is 1064 nm, repetition rate 357MHz, pulse width 7psec(FWHM) and a 42 cm long Fabry-Perot optical cavity. The experimental results show that laser power in the optical cavity can be enhanced by laser pulse stacking.  
 
THPLT065 Study of Multiturn Injection at HIMAC Synchrotron laser, vacuum, injection, antiproton 2637
 
  • T.H. Uesugi, T. Furukawa, T. Naruse, K. Noda
    NIRS, Chiba-shi
  • T. Fujimoto, S. Shibuya
    AEC, Chiba
  In the multiturn injection method at the HIMAC synchrotron, a collapsing speed of the bump orbit was decreased from 200 to 350 microseconds in order to obtain higher intensity beam. The injection line was readjusted to satisfy the optimum condition of multiturn injection method. Furthermore, COD correction and bump-orbit optimization were carried out. On the other hand, in order to prevent the resonance by tune shift and to keep the beam intensity constant, tune survey was carried out. While vertical tune is adjusted, we propose that the method to reduce beam loss after injection by expanding vertical beam size by means of the RF-knockout. This paper describes the improvement of injection at HIMAC synchrotron.  
 
THPLT066 Commissioning of 150MeV FFAG Synchronisation laser, vacuum, antiproton, emittance 2640
 
  • Y. Yonemura, M. Matoba
    Kyushu University, Fukuoka
  • M. Aiba, M. Sugaya
    University of Tokyo, Tokyo
  • S. Machida, Y. Mori, A. Muto, J. Nakano, C. Ohmori, I. Sakai, Y. Sato, A. Takagi, T. Yokoi, M. Yoshii, M. Yoshimoto, Y. Yuasa
    KEK, Ibaraki
  • T. Uesugi
    NIRS, Chiba-shi
  • A. Yamazaki
    LNS, Sendai
  A 150MeV proton FFAG (Fixed Field Alternating Gradient) synchrotron has been constructed to be a prototype for various applications such as proton beam therapy. At the moment, all the components are assembled, and multi-turn injection and beam storage were successfully performed. We are in the phase of beam acceleration up to final energy and expect the beam extraction in a few months. In this paper, beam commissioning results such as multi-turn injection, orbit correction, tune survey and optimization of RF gymnastics will be presented.  
 
THPLT067 Development of Optical Diffraction Radiation Beam Size Diagnostics at KEK Accelerator Test Facility laser, vacuum, antiproton, cathode 2643
 
  • V. Karataev, H. Hayano, T. Muto, N. Terunuma, J. Urakawa
    KEK, Ibaraki
  • R. Hamatsu
    TMU, Hatioji-shi,Tokyo
  • A. Naumenko, A.P. Potylitsyn
    Tomsk Polytechnic University, Physical-Technical Department, Tomsk
  Extremely low emittance high current beam is required for the accelerators of the next generation such as linear collider to achieve a reasonable luminosity. However, up to now there is no a simple non-invasive technique for beam diagnostics. A method based on optical diffraction radiation (ODR) appearing when a charged particle passes through a slit between two semi-planes can be one of the promising approaches. The estimations show that it might be possible to measure the beam size as small as 10mcm for a single shot. For a test of the proposed technique we designed an experimental setup and installed it at the extraction line of the KEK-ATF (1.26GeV beam energy, 1010 e/bunch, rms beam size > 10mcm). The electron beam was moving through a 0.26mm wide slit. We have measured backward ODR angular distribution. We have observed the beam size effect on the measured quantities. The sensitivity to the beam size as small as 20mcm was achieved. However, some undesirable factors such as X-ray background, SR photons coming through the mask slit, big detector angular acceptance have to be reduced. In this case a few micrometers beam size could be measured.  
 
THPLT068 Transverse Bunch-by-bunch Feedback System for the SPring-8 Storage Ring laser, antiproton, cathode, cyclotron 2646
 
  • T. Nakamura, S. Daté, T. Ohshima
    JASRI/SPring-8, Hyogo
  • K. Kobayashi
    SES, Hyogo-pref.
  A transverse bunch-by-bunch feedback system is developed for the SPring-8 storage ring. An analog de-multiplexer is developed to slice out every six-bunch signal for high-resolution 12-bit ADCs of clock frequency 85MHz, one-sixth of 508MHz RF frequency. Six commercial ADC-FPGA-DAC boards are used for processing the signal from the de-multiplexer. A custom FPGA board is used to multiplex the output signals from those boards. The feedback system is installed in the ring and working with the damping time of 0.5~2.5ms in 30kHz-254MHz and can suppress multi-bunch instabilities driven by impedances of resistive-wall of in-vacuum insertion devices and cavity HOMs at low chromaticity operation.  
 
THPLT069 High Speed Beam Loss Monitor and its Deterioration by Radiation laser, antiproton, cathode, cyclotron 2649
 
  • T. Kawakubo, T. Ishida, T. Sanami
    KEK, Ibaraki
  High speed loss monitor is very useful for tuning and operating the beam in an accelerator, especially in the injection and extraction period. We made a new type loss monitor by connecting a fiber to a photo-multiplier (PMT). In the case that the fiber is made of quartz, the source of the signal is Cherenkov effect. And in the case of scintillation fiber, the signal comes from the scintillation effect. The quartz is much stronger than the scintillator to the radiation, but generating light in the quartz is weaker than scintillator, especially in low energy beam. It is very easy to make this monitor and the fabrication cost is cheap. The monitor can observe the bunch loss with an order of 10 ns. After long time use under high irradiation, the signal of the monitor will decrease. Therefore, we also report the dependence of the signal strength on accumulated radiation in various types of material.  
 
THPLT070 Design and Constriction of Coronagraph for Observation of Beam Halo laser, antiproton, cathode, cyclotron 2652
 
  • T. Mitsuhashi
    KEK, Ibaraki
  The coronagraph is a spatial telescope to observe the sun-corona by artificial eclipse. The concept of this apparatus is to realize the Schlieren-optical system for cutting the bright diffraction fringes in order to observe a less-bright object surrounding the main image such as the sun-corona. We applied this concept for the observation of the surrounding structure (halo, tail) of the beam. Since the background is mainly scattered light come from the objective lens, the key point to observe a less-intense object is to reduce scattering light from objective lens. We used a very well-polished lens (better than scratch and dig 20/20) as objective lens, and succeeded to obtain the signal to background ratio better than 10-5. As a test, we tried to observe the tail of beam by hiding the central peak with artificial eclipse by the coronagraph at Photon Factory storage ring. We succeeded to observe the tail of beam which has an intensity range of 1/104 of the peak intensity.  
 
THPLT071 Upgraded Symplectic 3D Beam Tracking of the J-PARC 3 GeV RCS laser, antiproton, cathode, cyclotron 2655
 
  • M.J. Shirakata, H. Fujimori, Y. Irie
    KEK, Ibaraki
  The J-PARC 3 GeV ring is a rapid cycling synchrotron which consists of the large bore size magnets. The beam tracking with the 3D distributed magnetic fields is kept developing in order to investigate the beam injection process. In the case of the high intensity hadron accelerator, an accurate beam simulation is important for the designing because a very small amount of beam loss can be critical from the maintenance point of view. In order to improve the tracking accuracy and to save the calculation time, the symplectic integration with the fractal decomposition method has been introduced. The updated simulation results of the beam injection on the J-PARC 3 GeV RCS and the improved performance of ‘GenericSolver' are presented in this paper. The quadrupole fields are also treated as the 3D distributed magnetic fields because they interfered with the bump magnet fields. The remarkable features on the large bore magnet system in the ring accelerator are also discussed.  
 
THPLT072 Magnet and RF Systems of Small Pulse Synchrotron for Radiotherapy laser, antiproton, cathode, cyclotron 2658
 
  • K. Endo, K. Egawa, Z. Fang, S. Yamanaka
    KEK, Ibaraki
  To cure the malignant tumor it is desirable to equalize the treatment level to everybody anywhere he lives in. Proton and/or carbon-ion therapy are now considered as a powerful remedy as the radiation dose can be easily concentrated to the target volume by utilizing the Bragg?s peak. If a small medical accelerator is developed at a reasonable cost, it has a big potential to promote the advanced medical treatment with the accelerator in every place. This pulse synchrotron aims to reduce the size of the accelerator by generating the high magnetic field in a short time which leads to a compact ring of high field magnets. Acceleration time is only 5 msec by using the discharge current of a capacitor bank as large as 200 kA at peak, almost equivalent to half sinusoidal 50 Hz. Part of the discharge current is branched to excite the quadrupole magnets to assure the tracking between the dipole and quadrupole fields. Pulsed power technique is also adopted to drive the RF power tubes. Both magnet and RF systems have been developed and being extensively studied. Technological sides of both systems will be treated in details as well as the computational beam behaviors in this pulse synchrotron.  
 
THPLT073 Numerical Methods for the Orbit Control at the KEK 12 GeV PS laser, antiproton, cathode, cyclotron 2661
 
  • Y. Hitaka, H. Sato, M.J. Shirakata
    KEK, Ibaraki
  • M.K. Kono, Y.M. Yokomichi
    Miyazaki University, Miyazaki
  At the KEK 12GeV-PS main ring, when the least square method is applied to correct whole beam orbit all at once, it remains unacceptable beam loss and it is necessary to adjust the local positions of the beam orbit by hands with the beam loss monitors until the beam loss is suppressed under an acceptable level. However, the orbit does not realize the minimum-loss condition. In this paper, a new method is proposed. It focuses a fact that the beam loss distribution depends on the shape of the beam orbit and formulates this relationship to a functional approximation by using a nural network algorithm. Then, solving an optimization problem for generated network system, data of the beam shape which is more suitable for the beam loss of the accelerator can be obtained. The description of the system construction and experimental results are presented.  
 
THPLT074 The Beam Loss Monitor System of the J-parc LINAC, 3 GEV RCS and 50 GEV MR laser, antiproton, cathode, cyclotron 2664
 
  • S. Lee, T. Toyama
    KEK, Ibaraki
  • J. Kishiro
    JAERI/LINAC, Ibaraki-ken
  • M. Tanaka
    JAERI, Ibaraki-ken
  The high intensity beam accelerator complex itself requires the significant progress of design study and hardware R&D. Operational beam intensity should be limited by the beam loss and activation level of the equipment. Once the beam loss exceeds a criterion at outer environment, beam intensity has to be decreased to prevent the further activation. In order to investigate loss mechanism and suppress the beam loss, a beam loss monitor system have been developed for the J-PARC linac, 3 GeV RCS and 50GeV MR. The system will be essential component for beam commissioning, tuning and machine protection in high intensity beam accelerators. The loss monitor system is composed of scintillator, argon-methane/3He gas filled proportional counter and air filled coaxial cable ionization chamber, which detect g-ray, neutron and charged particles induced by lost particle. It is necessary to measure wide dynamic range of loss intensity for various beam energies. To prevent the activation and heat load by intense beam loss, fast time response of loss signals is required. In this paper, construction and application of loss monitor system are described in detail. Preliminary result of demonstration in the KEK-PS and calibration with cobalt 60 g-ray radiation source are also discussed.  
 
THPLT076 Compact X-band (11.424 Ghz) Linac for Cancer Therapy laser, antiproton, cathode, cyclotron 2667
 
  • N.H. Quyet, K. Dobashi, F. Ebina, M. El-Ashmawy, A. Fukasawa, H. Iijima, H. Ogino, M. Uesaka
    UTNL, Ibaraki
  Since most of medical linacs use S-band frequency, so far, such linacs cannot fit to modern advanced treatment techniques such as Tomotherapy and Stereotactic radiotherapy, which allows physicians to locate the tumor position during treatment time and enable for beam modification based on the real time analysis. Therefore, a new generation of electron linac with the compact size, higher power, higher gradient that can supply the advanced requirements of cancer treatment has been become necessary. X-band frequencies range is one of the suitable frequencies range for design such linacs. In this paper we will describe the possible design of a X-band (11.424 GHz) medical linac with side-coupled standing wave structure which understudying in NERL, The University of Tokyo. We aim to couple the therapy machine to the Compton scattering tunable monochromatic X-ray inspection device to realize the simultaneous inspection/therapy. Detailed design and numerical results are presented.  
 
THPLT077 MPI Parallel Computation of Wake Fields by Using Time Domain Boundary Element Method laser, antiproton, simulation, cathode 2670
 
  • K. Fujita, H. Kawaguchi
    Muroran Institute of Technology, Department of Electrical and Electronic Engineering, Muroran
  • T. Weiland, I. Zagorodnov
    TEMF, Darmstadt
  This paper presents wake field and wake potential calculation by using the Time Domain Boundary Element Method (TDBEM) on the MPI parallel computation system. The TDBEM is based on the electric field integral equation (EFIE) and the electric field integral equation (MFIE) in time domain. In wake field simulation, an important advantage of these equations is that electromagnetic fields in an accelerator cavity are explicitly expressed as a sum of charged particle self-fields and wake fields in time domain. On the other hand, the TDBEM has serious difficulties in practical numerical simulation, such as numerical instabilities, huge memory requirements, and heavy calculation cost. However, recent remarkable progress of computer performance makes the TDBEM possible to be used in practical simulations. According to these backgrounds, we apply the TDBEM to wake field simulation in the MPI parallel computer system. Simulation results are compared with that of a conventional method, the Finite Integration Techniques (FIT), and good agreements are shown.  
 
THPLT078 Construction of FFAG Accelerators in KURRI for ADS Study laser, antiproton, simulation, booster 2673
 
  • M. Tanigaki, K. Mishima, S. Shiroya
    KURRI, Osaka
  • S. Fukumoto, Y. Ishi
    Mitsubishi Electric Corp, Energy & Public Infrastructure Systems Center, Kobe
  • M. Inoue
    SLLS, Shiga
  • S. Machida, Y. Mori
    KEK, Ibaraki
  KART (Kumatori Accelerator driven Reactor Test) project has started at Kyoto University Research Reactor Institute (KURRI) from the fiscal year of 2002. The purpose of this project is to demonstrate the basic feasibility of ADS, studying the effect of incident neutron energy on the effective multiplication factor of the subcritical nuclear fuel system. We are now constructing a proton FFAG accelerator complex as a neutron production driver for this project. Our accelerator complex consists of a 2.5 MeV FFAG betatron as an injector and 20 MeV and 150 MeV FFAG synchrotrons as a booster and a main ring, respectively. Our FFAG betatron is a spiral sector type. Both booster and main rings are radial sector type FFAG synchrotrons, but different in the production of required magnetic field with a certain magnetic field index. The distribution of magnetic field is determined by the shaped pole-face in the main ring while the magnetic field is realized by use of trim coils in the booster ring. This FFAG complex will be combined with our Kyoto University Critical Assembly (KUCA) in KURRI by the end of March 2006 and the experiments will begin as soon as the whole system is ready.  
 
THPLT079 The Study of APF-IH Linac laser, antiproton, booster, cathode 2676
 
  • K. Yamamoto, T. Hattori, K. Yamamoto
    RLNR, Tokyo
  • M. Okamura
    RIKEN, Saitama
  • S. Yamada
    NIRS, Chiba-shi
  We have manufactured the IH linac with Alternating Phase Focus as the test machine of medical accelerator injection. It will accelerate C4+ ion up to 2MeV/u from 40 keV/u, the tank length is around 1.5m, operation frequency is 100MHz. Furthermore, We have succeeded the acceleration test using proton with simple acceleration system consist of P.I.G. ion source, bending magnets and focus lenses, less than 5m long. Otherwise, We have been making the program of beam dynamics with the results of the electro-magnetic simulation soft (Micro-Wave-Studio,OPERA-3D), it has the merit of easily to calculate the 3D- beam dynamics in the tank. We will report the some results of the test and the beam simulation and the comparisons.  
 
THPLT080 Simulation Study of the Beam Loading Effect in an RF Gun laser, antiproton, booster, cathode 2679
 
  • K. Shinto, H. Hama, F. Hinode, A. Miyamoto, T. Tanaka
    LNS, Sendai
  Because of simple structure and apparatus, a thermionic rf gun has been considered to be employed in a new pre-injector for the future synchrotron radiation facility at Tohoku University. A 3-D beam simulation code for the rf gun using a Finite Difference Time Domain (FDTD) method to solve Maxwell's equations has been developed. In the rf gun, especially in case of the high beam current, electromagnetic fields induced by the electron beam are considered to affect beam characteristics such as beam emittance and energy spread. In the FDTD method, because the Maxwell?s equations are able to be solved including the term of current density of the charge, the electromagnetic fields produced by both the external rf power and the electron beam can be anticipated. Using the simulation code, beam loading effects on the characteristics of the electron beam extracted from the rf gun is investigated.  
 
THPLT102 Characteristics of Sealed-off Electron Gun with Wide Beam plasma, antiproton, emittance, feedback 2724
 
  • V.M. Pirozhenko
    MRTI RAS, Moscow
  • A.N. Korolev, K.G. Simonov
    ISTOK, Moscow Region
  Compact sealed-off electron gun is a new promising type of devices. The gun generates wide beam of electrons with energy up to 200 keV and high peak power in 2-microsecond pulses. The beam is extracted to the atmosphere or a gas through the foil being uniformly distributed over the area of exposure. The gun contains the long ribbon cathode of oxide type, the electrodes for forming required distribution of the beam, the output window with 20-micron titanium foil, the high-voltage ceramic insulator, and the vacuum casing of rectangular shape. The gun is applied in the radiation technology system intended for the treatment of continuously moving tapes with 300 mm width. The gun design provides 10% uniformity of the radiation dose on the tape width.  
 
THPLT106 Measurement of Beam Polarization in VEPP-3 Storage Ring using Internal Target-based Moeller Polarimeter plasma, antiproton, polarization, emittance 2727
 
  • A.V. Grigoriev, V. Kiselev, E.V. Kremyanskaya, E. Levichev, S.I. Mishnev, S.A. Nikitin, D.M. Nikolenko, I.A. Rachek, Y.V. Shestakov, D.K. Toporkov, V.N. Zhilich
    BINP SB RAS, Novosibirsk
  A method for beam polarization measurement in a storage ring has been for the first time developed and applied based on measuring the asymmetry in scattering of polarized beam electrons on the internal polarized gas jet target. Using this method we have studied the polarization in VEPP-3 booster storage ring. VEPP-3 is the source of polarized beams for VEPP-4M electron-positron collider in the planned experiment on high-precision mass measurement of tau-lepton near the production threshold of the latter (1777 MeV). Radiative polarization of beams obtained in VEPP-3 is used for absolute calibration of particle energy by the resonant depolarization technique after injection into VEPP-4M ring. The polarimeter design is described. Results of polarization measurements performed in 60 MeV range of VEPP-3 energy contiguous from above to tau-lepton production threshold are presented and discussed. The depolarizing influence of the integer machine spin resonance (1763 MeV) as well as of the combination spin resonances with the betatron frequencies are found to be significant.  
 
THPLT107 VEPP-4M Optical Beam Profile Monitor with a One-turn Temporal Resolution plasma, antiproton, polarization, emittance 2730
 
  • O.I. Meshkov, V.F. Gurko, A.D. Khilchenko, V. Kiselev, N.Y. Muchnoi, N.A. Selivanov, V.V. Smaluk, A.N. Zhuravlev, P.V. Zubarev
    BINP SB RAS, Novosibirsk
  The transverse beam profile monitor based on Hamamatsu multi-anode photomultiplier with 16 anode strips is used at the VEPP-4M collider. The monitor is applied to study turn-to-turn dynamics of the transverse beam profile during 131 000 turns. The device provides a permanent measurement of synchrotron and betatron frequencies as well.  
 
THPLT108 The Study of the Beam TAILS with the Optical Coronagraph plasma, antiproton, polarization, emittance 2733
 
  • O.I. Meshkov, M.G. Fedotov, E.V. Kremyanskaya, E. Levichev, N.Y. Muchnoi, Yu.A. Pakhotin, N.A. Selivanov, A.N. Zhuravlev
    BINP SB RAS, Novosibirsk
  Optical white-light Lyot coronograph is applied at the VEPP-4M collider to study the "tails" of the transverse beam profile. The device is used for investigation of the beam-beam effects.  
 
THPLT109 The Upgraded Optical Diagnostic of the VEPP-4M Collider plasma, antiproton, polarization, emittance 2736
 
  • O.I. Meshkov, M.G. Fedotov, V.F. Gurko, A.D. Khilchenko, N.Y. Muchnoi, Yu.A. Pakhotin, N.A. Selivanov, A.N. Zhuravlev, E.I. Zinin, P.V. Zubarev
    BINP SB RAS, Novosibirsk
  The upgraded optical diagnostic of the VEPP-4M collider is described. The system abilities are improved sufficiently in comparing with the previous version. Now the diagnostic supplies the data about an electron/positron beam transversal and longitudinal size, shape and position. It is applied to study the electron beam "tails" and turn-to-turn beam profile dynamics. The system is used to tune of the beam pass-by from the VEPP-3 booster to the VEPP-4M collider and provides the permanent measurements of the synchrotron and betatron frequencies.  
 
THPLT110 Modelling of Accelerating Structures with Finite-difference Time-domain Method plasma, antiproton, polarization, emittance 2739
 
  • E.V. Pickulin, V.N. Malyshev
    LETI, Saint-Petersburg
  • S.A. Silaev, Y.A. Svistunov
    NIIEFA, St. Petersburg
  A finite-difference time-domain (FDTD) method is very popular for electromagnetic field modeling. The practical interest in the method is the ability to calculate fields in time domain at any time point in the accelerating structure. That is to say the FDTD method is able to model transient process taking into account the peculiarity of RF power input device. A FDTD approach for modeling of alternate phase focusing structure is presented in this paper. The modeling of lossy metals is a problem in classical formulation of FDTD method. This matter is investigated and one of the solutions is presented in this paper. There are some problems of signal processing when using time-domain method for resonant structure modeling. The matters of mode determination are also investigated and presented in this paper. The simulation results are compared with experimental data.  
 
THPLT111 An Accelerator-based Thermal Neutron Source for BNCT Application plasma, antiproton, polarization, emittance 2742
 
  • A. Makhankov, A. Gervash, R. Giniyatulin, I. Mazul, M. Rumyantsev
    NIIEFA, St. Petersburg
  • J. Esposito, L.B. Tecchio
    INFN/LNL, Legnaro, Padova
  • V. Khripunov
    RRC Kurchatov Institute, Moscow
  An accelerator-based thermal neutron source, aimed at the BNCT treatment of skin melanoma is in construction at the INFN-LNL in the framework of SPES project. The BNCT device exploit the intense proton beam provided by a 5 MeV, 30 mA RFQ that represent the first accelerating step of the SPES exotic nuclei production beam facility. Neutrons are generated by 9Be(p,n)9B nuclear reaction in a high power (150 kW) Beryllium target. The operational condition of the Beryllium converter is close to the condition of Be-armoured components in fusion reactors. The main difference consists in the necessity of limitation of structural materials amount used in the design in order to meet therapeutic irradiation requirements. Two possible design of neutron converter are developed: one with saddle block tiles brazed to CuCrZr tubes and another one with Be target made from solid Be block. Results of R&D works on the development of water cooled Be target for converter are presented, including data on selected materials, technological trials and mockups high heat flux testing.  
 
THPLT112 Methods and Instrumentation for Measurement of Low Ion Beam Currents at Cryring plasma, antiproton, polarization, emittance 2745
 
  • A. Paal, A. Källberg, A. Simonsson
    MSL, Stockholm
  • J. Dietrich, I. Mohos
    FZJ/IKP, Jülich
  In many CRYRING experiments an accurate measurement of the circulating ion beam current is essential for determination of e.g. absolute cross sections. However, the current produced from the ion source can be very low. Furthermore, when surface barrier detectors are used, for example in the merged electron-ion beam experiments, the current has to be kept low to avoid saturation. With new electronics, using an Integrating Current Transformer with 5 V/A sensitivity, the current resolution of the Bergoz Beam Charge Monitor (BCM) has been increased to below 1 nA for bunched beams. The sum signal of the capacitive pick-up located at the farthest point from the RF-system is integrated by a second gated integrator. The RMS resolution is about 100 pA. To measure the intensity of coasting beams neutral particle detectors and a residual-gas beam profile monitor are used, calibrated with the BCM output during 20-100 ms after acceleration. The micro-channel plate detectors can handle a few Mcps count rate with a maximum 1 cps dark count rate. Presently a 50 Mcps secondary electron multiplier is being tested as a neutral particle monitor, having a maximum dark count rate of 0.05 cps  
 
THPLT113 Conceptual Design of a Microwave Confocal Resonator Pick-up plasma, antiproton, polarization, emittance 2747
 
  • V.G. Ziemann, A. Ferrari, T. Lofnes
    TSL, Uppsala
  • F. Caspers, I. Syratchev
    CERN, Geneva
  A confocal resonator may be used as a pick-up for frequencies in the multi-GHz region. In this report we discuss the design by analytical and numerical methods of such a device. Furthermore we discuss engineering issues such as the damping of unwanted modes, shielding of image fields and manufacturing tolerances. Such a device can be used both as pick-up and kicker where the actual structure is several wavelengths away from the beam in the transverse direction. It is intended for highly relativistic beams and does not require changing particle trajectory as opposed to a diagnostic wiggler.  
 
THPLT114 A New Mono-energetic Neutron Beam Facility in the 20-180 MeV Range plasma, antiproton, polarization, emittance 2750
 
  • V.G. Ziemann, L.-O. Andersson, T. Bergmark, O. Bystrom, A. Bäcklund, H. Calen, L. Einarsson, C. Ekström, J. Fransson, K.J. Gajewski, N. Haag, T. Hartman, E. Hellbeck, T. Johansen, O. Jonsson, B. Lundström, R.P. Peterson, L. Pettersson, A. Prokofiev, D. Reistad, P.-U. Renberg, R. Wedberg, D. Wessman, L. Westerberg, D. van Rooyen
    TSL, Uppsala
  • J. Blomgren, S. Pomp, U. Tippawan, M. Österlund
    INF, Uppsala
  Recent interest in nuclear applications involving neutrons, like ransmutation of nuclear waste, fast-neutron cancer therapy, dose to personnel in aviation and electronics failures due to cosmic-ray neutrons, motivate the development of a facility producing intense mono-energetic neutron beams. At The Svedberg laboratory (TSL), Uppsala, Sweden, we have developed such a facility by utilizing the existing cyclotron and inserting a flexible Lithium target in a rebuilt beam line. The new facility can operate at unsurpassed quasi-monoenergetic neutron intensities and provides large flexibility of the neutron beam properties, like diameter and shape.  
 
THPLT122 The Energy Deposition Profile of 0.1-3.0 MeV Electrons in NaCl plasma, antiproton, polarization, emittance 2753
 
  • V.V. Gann
    NSC/KIPT, Kharkov
  • A.V. Sugonyako, D.I. Vainshtein, H.W. den Hartog
    RUG, Groningen
  An analysis is presented of existing experimental and theoretical data of energy loss profiles and energy deposition in thick targets irradiated with MeV-energy electrons. A simple approximate calculation is proposed for the energy deposition profile of a perpendicular beam of 0.1-3 MeV electrons in matter. The results obtained with this method are in agreement with existing calculated and measured energy absorption profiles for a variety of materials. It will be shown that the build-up phenomenon has a significant effect on the energy deposition profile in thick samples. A systematic experimental investigation of the energy deposition profile of 0.5 MeV electrons in 0.2 - 0.8 mm thick NaCl platelets has been carried out. The distribution of the absorbed dose was determined with differential scanning calorimetry method by measuring either the latent heat of melting of the radiation-induced Na-precipitates or the stored energy.  
 
THPLT123 Coupling Coefficients in the Inhomogeneous Cavity Chain plasma, antiproton, polarization, emittance 2756
 
  • K. Kramarenko, M.I. Ayzatskiy
    NSC/KIPT, Kharkov
  In this paper a mathematical method on the base of a rigorous electrodynamic approach for description of inhomogeneous chain of cylindrical cavities is presented. The form of the obtained for chosen amplitudes set of equations is similar to the set of equations that describe the simple coupled circuit chain. As the cavity have the infinite number of resonant frequencies, to obtain the coupling coefficients one have to solve additional infinite set of linear equations with coefficients that depend on the frequency. Using the developed method in the case of inhomogeneous cavity chain we calculated the dependence of the coupling coefficients on frequency and geometrical sizes with taking into account the 'long-range' coupling.  
 
THPLT124 Simulation Technique for Study of Transient Self-consistent Beam Dynamics in RF Linacs plasma, antiproton, polarization, emittance 2759
 
  • V.V. Mytrochenko, A. Opanasenko
    NSC/KIPT, Kharkov
  The report describes a simulation technique for study of unsteady self-consistent dynamics of charged particles in resonant linacs. The technique allows simulating the linacs that consist of resonant cavities and traveling wave sections. The proposed approach is based on unsteady theories of excitation of resonant cavities and waveguides by a beam of charged particles and RF feeders. The theory of waveguide excitation is generalized to the case of spatially inhomogeneous traveling wave structures. The system of self-consistent differential equations for fields and motion of particles is integrated over time and space. The SUPERFISH code is used to evaluate characteristics of the axially symmetrical cavities and traveling wave sections. The PARMELA code is applied to simulate motion of the particles at each time step of the integration. In such a way the fields and beam characteristics in the axially symmetrical accelerating structures can be obtained for transient and steady state operation. Description of the algorithm and results of its validation are presented.  
 
THPLT127 Beam Diagnostics Systems for the Diamond Synchrotron Light Source plasma, antiproton, polarization, electron 2762
 
  • G. Rehm, A.F.D. Morgan, C. Thomas
    Diamond, Oxfordshire
  We present an overview of the diagnostics systems that will be implemented at the Diamond synchrotron light source. The aim of this paper is to give a complete picture of the systems to measure the quality of the electron beam from the injector through to the storage ring. We will show how we intend to measure the dimensions, the position and the time structure of the electron bunches. In addition, the instrumentation to measure the charge, the current and the emittance of the electron beam will be described. Finally, systems to provide accurate measurement of electron losses and the injection efficiency will be detailed.  
 
THPLT129 Ion Chambers for Monitoring the NuMI Beam at FNAL plasma, antiproton, proton, polarization 2765
 
  • S.E. Kopp, D. Indurthy, R. Keisler, S. Mendoza, Z. Pavlovich, M. Proga, R.M. Zwaska
    The University of Texas at Austin, Austin, Texas
  • M. Diwan, B. Viren
    BNL, Upton, Long Island, New York
  • A.R. Erwin, H.P. Ping, C.V. Velisaris
    UW-Madison/PD, Madison
  • D. Harris, A. Marchionni, J. Morfin
    Fermilab, Batavia, Illinois
  • J. McDonald, D. Naples, D. Northacker
    University of Pittsburgh, Pittsburgh, Pennsylvania
  We summarize selected instrumentation under construction for the NuMI neutrino beam facility at Fermilab. An array of foil secondary emission monitors (SEM's) will measure the 120GeV proton beam position, profile and halo at 10 stations along the transport to the NuMI target. The final two foil SEM's align the proton beam to within 50 microns on target. These are capable of withstanding the 400kW proton beam and causing <5·10-6 beam loss. Further instrumentation includes four stations of ionization chambers located downstream of the decay volume, one upstream and three downstream of the beam dump. The latter three monitor the tertiary muon beam, the first monitors the remnant hadron beam. The ion chamber arrays align the proton beam to 14microRadian and the neutrino beam to within 50 microRadian, as well as monitoring flux to better than 1%. The ion chambers are designed to withstand the ~1GRad doses and 109 particle/cm2/spill fluxes anticipated during NuMI beam operations. Beam tests and R&D efforts are discussed.  
 
THPLT130 Synchronization of the Fermilab Booster and Main Injector for Multiple Batch Injection plasma, proton, polarization, electron 2768
 
  • R.M. Zwaska, S.E. Kopp
    The University of Texas at Austin, Austin, Texas
  • W. Pellico, R.C. Webber
    Fermilab, Batavia, Illinois
  To date, the 120 GeV Fermilab Main Injector accelerator has accelerated a single batch of protons from the 8 GeV rapid-cycling Booster synchrotron for production of antiprotons for Run II. In the future, the Main Injector must accelerate 6 or more Booster batches simultaneously; the first will be extracted to the antiproton source, while the remaining are extracted for the NuMI/MINOS neutrino experiment. Performing this multi-batch operation while avoiding unacceptable radioactivation of the beamlines requires a previously unnecessary synchronization between the accelerators. We describe a mechanism and present results of advancing or retarding the longitudinal progress of the Booster beam by active feedback radial manipulation of the beam during the acceleration period.  
 
THPLT133 Simulation of RF Control of a Superconducting Linac for Relativistic Particles plasma, proton, polarization, electron 2771
 
  • M. Huening, P. Bauer, G.W. Foster
    Fermilab, Batavia, Illinois
  We present a code to simulate the rf field and field control in a superconducting linac for relativistic heavy particles. In such a linac the field stability is strongly influenced by the longitudinal beam dynamics. So the code has to simulate both the field and the beam dynamics with the resulting varying beam loading. Other effects included in the simulation are Microphonics and Lorentz force. The code can simulate both single cavity and vector sum control.  
 
THPLT135 Experience with the 1.7 GHz Schottky Pick-ups in the Tevatron plasma, proton, polarization, electron 2774
 
  • A. Jansson, P. Lebrun, R. Pasquinelli
    Fermilab, Batavia, Illinois
  During a 2003 shutdown, new high-frequency Schottky pick-ups were installed in the Tevatron. These devices operate at 1.7 GHz (harmonic ~36000 of the revolution frequency) and can in principle be used to measure tunes, chromaticities, momentum spread and transverse emittances of individual bunches. Only the transverse signal is used, as the longitudinal is dominated by coherent signal. The default mode of operation during a store is to sequentially acquire and analyze frequency data from different sets of bunches in the machine. This function is performed by an open access client written in Java/C++, running in the background. The resulting fit parameters are datalogged and can also be plotted in "real time" during the store. With an alternative setup, data from select bunches can be acquired continuously during the entire ramp (and squeeze), for analysis off-line. This paper describes the evolution, current status and performance of the acquisition and analysis software, and presents measurements with comparison to predictions and other measurement techniques. One example of such a measurement is the variation of beam-beam tune shift as a function of intensity and bunch position within a train.  
 
THPLT137 Commissioning of the Head-tail Monitoring Application for the Tevatron plasma, proton, polarization, electron 2777
 
  • V.H. Ranjbar, V. Lebedev, E. Lorman, A. Xiao
    Fermilab, Batavia, Illinois
  A head-tail beam monitoring application has recently been developed for use in the Tevatron. With this application beam dynamics problems including head-tail instabilities can be monitored. In addition it can be use to perform chromaticity measurements using the head-tail technique developed at CERN. This application speeds up chromaticity measurements in the Tevatron especially during the acceleration ramp and low beta squeeze, which previously required three separate ramps using uncoalesced protons  
 
THPLT140 Commissioning of BL 7.2, the New Diagnostic Beamline at the ALS plasma, proton, polarization, booster 2780
 
  • F. Sannibale, D. Baum, A. Biocca, N. Kelez, T. Nishimura, T. Scarvie, E. Williams
    LBNL, Berkeley, California
  • K. Holldack
    BESSY GmbH, Berlin
  BL 7.2 is a new beamline at the Advanced Light Source (ALS) dedicated to electron beam diagnostics. The system, which is basically a hard x-ray pinhole camera, was installed on the storage ring in August 2003 and the commissioning with the ALS electron beam followed immediately after. In this paper, the commissioning results are presented together with the description of the relevant measurements performed for the beamline characterization.  
 
THPLT141 Operational Experience Integrating Slow and Fast Orbit Feedbacks at the ALS plasma, feedback, proton, polarization 2783
 
  • C. Steier, E.E. Domning, T. Scarvie, E. Williams
    LBNL, Berkeley, California
  A fast global orbit feedback system has been implemented at the ALS and is being used during user operation since this year. The system has two main purposes. The first is to meet the demands of some users for even improved (submicron) short term orbit stability. The second is to enable the use of more sophisticated insertion device compensation schemes (e.g. tune, beta-beating, coupling) for fast moving insertion devices like elliptically polarizing undulators, without deteriorating the orbit stability. The experience of routine user operation with the fast orbit feedback will be presented, as well as the overall feedback performance and how the integration issues with the already existing slow orbit feedback were solved.  
 
THPLT142 A Laser-Based Longitudinal Density Monitor for the Large Hadron Collider plasma, feedback, proton, polarization 2786
 
  • S. De Santis, J.F. Beche, J.M. Byrd, P. Datte, M. Placidi, V. Riot, R.W. Schoenlein, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  We report on the development of an instrument for the measurement of the longitudinal beam profile in the Large Hadron Collider. The technique used, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store and display the required information. A 40 MHz laser, phase-locked to the ring radiofrequency system, with a 50 ps pulse length, would be suitable for measuring the dynamics of the core of each of the LHC 2808 bunches in a time span much shorter then the synchrotron period. The same instrument could also monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets ("ghost bunches") as required by the CERN specifications. We also specify the required characteristics of the diagnostic light port in the LHC where our instrument would be installed.

* Presently at Lawrence Livermore National Laboratory.

 
 
THPLT143 Development of an Abort Gap Monitor for the Large Hadron Collider plasma, feedback, proton, polarization 2789
 
  • S. De Santis, J.F. Beche, J.M. Byrd, M. Placidi, W.C. Turner, M.S. Zolotorev
    LBNL, Berkeley, California
  The Large Hadron Collider, presently under construction at CERN, requires a monitor of the parasitic charge in the 3.3 ?s long gap in the machine fill structure, referred to as the abort gap, which corresponds to the raise time of the abort kickers. Any circulating particle present in the abort gap at the time of the kickers firing is lost inside the ring, rather than in the beam dump, and can potentially damage a number of the LHC components. CERN specifications indicate a linear density of 6x106 protons over a 100 ns interval as the maximum charge safely allowed in the abort gap at 7 TeV. We present a study of an abort gap monitor, based on a photomultiplier with a gated microchannel plate, which would allow for detecting such low charge densities by monitoring the synchrotron radiation emitted in the superconducting undulator dedicated to the measurement of the longitudinal beam properties. We show results of beam test experiments at the Advanced Light Source using an Hamamatsu 5916U MCP-PMT which indicate that such an instrument has the required sensitivity to meet LHC specifications.  
 
THPLT145 Automated High-power Conditioning of Medical Accelerators plasma, feedback, proton, polarization 2792
 
  • S.M. Hanna, S. Storms
    Siemens Medical Solutions USA, Inc., Oncology Care Systems Group, Concord
  Medical accelerators require arc-free operation. Due to high-field emission, arcing and outgasing can occur in high-power accelerators. Therefore, the accelerator?s inner surfaces have to be conditioned before its use at high gradient levels in Radiation Therapy machine. At Siemens, we have developed a techniqu·101 to automatically condition an accelerator waveguide structure by continually inspecting the accelerator running conditions (arcing and vacuum) and stepping up the pulse repetition frequency (PRF) and RF power until reaching maximum power rating. The program implemented also reads, displays, and archives the data it collects along the full process of conditioning.  
 
THPLT146 Beam Diagnostics of the Small Isochronous Ring plasma, feedback, proton, polarization 2795
 
  • J.A. Rodriguez, F. Marti
    NSCL, East Lansing, Michigan
  • E. Pozdeyev
    Jefferson Lab, Newport News, Virginia
  The purpose of this paper is to describe the beam diagnostic systems in the Small Isochronous Ring (SIR) developed and built at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). SIR is a small-scale experiment that simulates the dynamics of intense beams in large accelerators. A 20 to 30 keV hydrogen or deuterium ion bunch is injected in the ring, extracted after a variable number of turns and its longitudinal profile is studied. Some of the diagnostic tools available in SIR include an emittance measurement system in the injection line, scanning wires in different sections of the ring, phosphor screens at the injection and extraction points and a fast Faraday cup in the extraction line. The design of these systems and the kind of beam information they provide are discussed in detail.  
 
THPLT147 Beam Halo Monitoring on the CLIC Test Facility 3 plasma, feedback, proton, polarization 2798
 
  • T. Lefevre
    NU, Evanston
  • H.-H. Braun, E. Bravin, R. Corsini, A.-L. Perrot, D. Schulte
    CERN, Geneva
  In high intensity accelerators, the knowledge of the beam halo distribution and its generation mechanisms are important issues. In order to study these phenomena, dedicated beam diagnostics must be foreseen. In circular machines, beam halo was monitored by using scrapers and beam loss detectors. In the framework of the CLIC project, beam halo monitoring is currently under development. The proposed device is based on an imaging system and a masking technique, which suppresses the core of the beam to allow direct observation of the beam halo. A first test was performed on the CLIC test facility 3 in 2003. We discuss the performances and the limitations of this technique pointing out our plans for future developments.  
 
THPLT148 Beam Loss Monitoring on the CLIC Test Facility 3 plasma, feedback, proton, polarization 2801
 
  • T. Lefevre, M. Velasco, M. Wood
    NU, Evanston
  • H.-H. Braun, R. Corsini, M. Gasior
    CERN, Geneva
  The CLIC test facility 3 (CTF3) provides a 3.5A, 1.5s electron beam pulse of 150MeV at the end of the linac. The average beam power is 4 kW. Beam loss will be monitored all along the linac in order to keep the radiation level as low as possible. The heavy beam loading of the linac can lead to time transients of beam position and size along the pulse. To compensate these transients effectively a beam loss monitor (BLM) technology has to be chosen with a time response faster than a few nanoseconds. In this context, two different tests have been performed in 2003 on the already existing part of the CTF3 accelerator. Several detectors based on different technologies were first tested in parallel to determine which one was the most appropriate. A second test, in which the beam was intentionally lost in well defined conditions, was then made with the aim of comparing the measurements with simulation results. We present here the results of these tests and our conclusion for the new system to be developed.  
 
THPLT150 Results from Orbit and Optics Improvement by Evaluating the Nonlinear Beam Position Monitor Response in CESR plasma, feedback, proton, polarization 2804
 
  • R.W. Helms, G. Hoffstaetter
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  In the Cornell Electron/positron Storage Ring (CESR), pretzel orbits with large horizontal oscillations are used to keep electron and positron beams out of collision except at the interaction point. Since a beam position monitor's (BPM's) response is only linear near the center of the beam pipe, the assumption of linearity does not allow for accurate orbit and phase measurements under colliding beam conditions. Using a numerical model of the BPMs' response to large offsets of the beam position, and an enhanced algorithm for real-time inversion of this nonlinear response function, we have extended our orbit and betatron phase measurements to beams with large pretzel amplitudes. Several measurements demonstrate the applicability, accuracy, and usefulness of this method.  
 
THPLT151 Evaluation of Beam Position Monitors in the Nonlinear Regime plasma, feedback, proton, polarization 2807
 
  • R.W. Helms, G. Hoffstaetter
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  Here we present a new algorithm for processing BPM signals and extracting orbit and phase data for very large beam excursion where the BPM response function changes nonlinearly with the beam position. Using two dimensional models of each BPM geometry, we calculate the button response using numerical solution of Laplace's equation and Green's reciprocity theorem. The difference between the calculated signals and the measured signals is minimized in real time to calculate the beam position and measurement errors. Using the derivatives of the response functions, we model the effect of beam shaking, and from it, calculate the betatron phase.  
 
THPLT152 Operation of the Position Measurements for the Isotope Production Facility plasma, feedback, proton, polarization 2810
 
  • J.D. Gilpatrick, D.S. Barr, L.J. Bitteker, M.S. Gulley, D.M. Kerstiens, D. Martinez, J.F. O'Hara, C. Pillai, R.B. Shurter
    LANL/LANSCE, Los Alamos, New Mexico
  The Isotope Production Facility (IPF) will provide isotopes for medical purposes by using a 100-MeV H+-beam spur beam line from the Los Alamos Neutron Science Center (LANSCE) facility. Beam position measurements for IPF use a standard micro-stripline beam position monitor (BPM) with both an approximate 50-mm and 75-mm radius. The associated cable plant is unique in that it unambiguously provides a method of verifying the operation of the complete position measurement. The processing electronics module uses a log ratio technique with an error correcting software algorithm so that each the overall position measurement is periodically calibrated over a dynamic range of > 86 dB with errors less than 0.1 dB within this range. A National Instruments LabVIEW virtual instrument performs automatic periodic calibration and verification, and serves the data via the Experimental Physics and Industrial Control System (EPICS) channel access protocol. In order to report the data to the LANSCE facility operators and accelerator physicists, the served data are displayed and archived. This paper will describe the measurement system, commissioning and initial operating experiences.  
 
THPLT153 Commissioning and Initial Operation of the Isotope Production Facility at the Los Alamos Neutron Science Center plasma, feedback, proton, polarization 2813
 
  • K.F. Johnson, H.W. Alvestad, W.C. Barkley, D.B. Barlow, D.S. Barr, G.A. Bennett, L.J. Bitteker, E. Bjorklund, W. Boedeker, M.J. Borden, R.A. Cardon, G. Carr, J.L. Casados, S. Cohen, J.F. Cordova, J.A. Faucett, M. Fresquez, F.R. Gallegos, J.D. Gilpatrick, F. Gonzales, F.W. Gorman, M.S. Gulley, M.J. Hall, D.J. Hayden, R.C. Heaton, D. Henderson, D.B. Ireland, G. Jacobson, G.D. Johns, D.M. Kerstiens, A.J. Maestas, A.R. Martinez, D. Martinez, G.C. Martinez, J. Martinez, M.P. Martinez, R. Merl, J.B. Merrill, J. Meyer, M.L. Milder, E.A. Morgan, F.M. Nortier, J.F. O'Hara, F.R. Olovas, M.A. Oothoudt, T.D. Pence, E.M. Perez, C. Pillai, F.P. Romero, C. Rose, L. Rybarcyk, G. Sanchez, J.B. Sandoval, S. Schaller, F.E. Shelley, R.B. Shurter, W. Sommer, M.W. Stettler, J.L. Stockton, J. Sturrock, T.L. Tomei, V.P. Vigil, P.L. Walstrom, P.M. Wanco, J. Wilmarth
    LANL/LANSCE, Los Alamos, New Mexico
  • R.E. Meyer, E.J. Peterson, F.O. Valdez
    LANL, Los Alamos, New Mexico
  The recently completed 100-MeV H+ Isotope Production Facility (IPF) at the Los Alamos Neutron Science Center (LANSCE) will provide radioisotopes for medical research and diagnosis, for basic research and for commercial applications. A change to the LANSCE accelerator facility allowed for the installation of the IPF. Three components make up the LANSCE accelerator: an injector that accelerates the H+ beam to 750-KeV, a drift-tube linac (DTL) that increases the beam energy to 100-MeV, and a side-coupled cavity linac (SCCL) that accelerates the beam to 800-MeV. The transition region, a space between the DTL and the SCCL, was modified to permit the insertion of a kicker magnet (23o kick angle) for the purpose of extracting a portion of the 100-MeV H+ beam. A new beam line was installed to transport the extracted H+ beam to the radioisotope production target chamber. This paper will describe the commissioning and initial operating experiences of IPF.  
 
THPLT154 Design of an X-ray Imaging System for the Low-Energy Ring of PEP-II plasma, feedback, proton, polarization 2816
 
  • A.S. Fisher, D. Arnett, H. De Staebler, S. Debarger, R.K. Jobe, D. Kharakh, D.J. McCormick, M. Petree, M.C. Ross, J. Seeman, B. Smith
    SLAC, Menlo Park, California
  • J. Albert, D. Hitlin
    CALTECH, Pasadena, California
  • J. Button-Shafer, J.A. Kadyk
    LBNL, Berkeley, California
  An x-ray beam-size monitor for positrons in the low-energy ring (LER) of the PEP-II B Factory at SLAC is being designed to accommodate the present 2-A, 3.1-GeV beam and anticipated currents of up to 4.7 A. The final photon stop of an arc will be rebuilt to pass dipole radiation through cooled apertures to optics 17 m from the source. Zone-plate imaging there can achieve a resolution of 6 microns, compared to 35 for a pinhole camera. Two multilayer x-ray mirrors precede the zone plate, limiting the bandwidth to 1%, in order to avoid chromatic blurring and protect the zone plate. Despite the narrow bandwidth, the zone plate?s larger diameter compared to a pinhole camera allows for a comparable photon flux. We will image all 1700 LER bunches and also measure them individually, searching for variations along the train due to electron-cloud and beam-beam effects, using a scanning detector conceptually derived from a wire scanner. A mask with three narrow slots at different orientations will scan the image to obtain three projections. In one passage, signals from a fast scintillator and photomultiplier will be rapidly digitized and sorted to profile each bunch.  
 
THPLT155 Development and Testing of a Low Group-delay Woofer Channel for PEP-II plasma, proton, polarization, booster 2819
 
  • J.D. Fox, L. Beckman, D. Teytelman, D. Van Winkle, A. Young
    SLAC, Menlo Park, California
  The PEP-II HER and LER require active longitudinal feedback to control coupled-bunch instabilities. The PEP-II RF systems use direct and comb loop feedback to reduce the cavity fundamental impedance, though the remaining low-mode impedance is providing the fastest growing unstable modes in both rings. Since commissioning the longitudinal feedback systems have used a dedicated "woofer" channel to apply the low-frequency correction kick via the RF system. The performance of this original controller is limited by the maximum gain that can be supported due to the processing delay (group delay), as well as the difficulty in configuring a common correction controller that acts via two correction paths. A dedicated low-mode signal processing system has been developed to allow higher damping rates. It is a digital processing channel, operating at a 10 MHz sampling rate, and implementing flexible 5 to 10 tap FIR control filters. The design of the channel and initial control filters is presented, as are initial machine experiments quantifying the damping and noise floor of this low group delay woofer system.  
 
THPLT156 Simulations of IP Feedback and Stabilization in the NLC plasma, proton, polarization, booster 2822
 
  • L. Hendrickson, J.C. Frisch, T.M. Himel, T.O. Raubenheimer, A. Seryi, M. Woodley
    SLAC, Menlo Park, California
  • G.R. White
    Queen Mary University of London, London
  Keeping nanometer-sized beams in collision is an essential component in achieving design luminosity in a linear collider. The NLC stabilization strategy is conservative by including enough redundancy so that if some piece doesn't work to specification or the incoming beam motion is worse than expected, the beams will still be kept in collision. We show simulation results with both realistic and pessimistic assumptions about the response of the ground motion, inertial stabilization, interbunch and intertrain feedback systems. By providing backup systems, and by assuming that some systems may perform more poorly than expected, we can achieve a high level of confidence in our ability to successfully stabilize the beams.  
 
THPLT157 Beam-based Feedback for the NLC Linac plasma, proton, polarization, booster 2825
 
  • L. Hendrickson, N. Phinney, A. Seryi, P. Tenenbaum, M. Woodley
    SLAC, Menlo Park, California
  The NLC linac train-by-train feedback system is designed to stabilize the beam trajectory, but is also a valuable element in the strategy for emittance preservation. New simulations employ improved strategies [*], allowing beam steering to be performed significantly less often than without the feedback system. Additional simulations indicate that the linac feedback can contribute towards successful operation at noisier sites.

* Beam-based Feedback Simulations for the NLC Linac, L. Hendrickson et al., LINAC, Monterey, California (2000)

 
 
THPLT159 Instability Thresholds and Generation of the Electron-cloud in the GLC/NLC and Tesla Damping Rings plasma, proton, polarization, electron 2828
 
  • M.T.F. Pivi, T.O. Raubenheimer
    SLAC/NLC, Menlo Park, California
  In the beam pipe of the Damping Ring (DR) of a linear collider, an electron cloud may be produced by ionization of residual gas and secondary emission. This electron cloud can reach equilibrium after the passage of only a few bunches. We present recent computer simulation results for the main features of the electron cloud generation in the GLC/NLC main DR and for the TESLA DR. Single and multi-bunch instability thresholds are also calculated for the NLC main DR. The results are obtained by the computer simulation codes HEAD-TAIL and POSINST, which were developed to study the electron cloud effect in particle accelerators.  
 
THPLT160 Measurements of Transverse Coupled-bunch Instabilities in PEP-II plasma, feedback, proton, polarization 2831
 
  • D. Teytelman, R. Akre, J.D. Fox, S.A. Heifets, A. Krasnykh, D. Van Winkle, U. Wienands
    SLAC, Menlo Park, California
  At the design currents the PEP-II High and Low Energy Rings operate above the coupled-bunch instability thresholds in horizontal and vertical planes. Both machines have used analog bunch-by-bunch feedback systems to stabilize the beams since commissioning. Here we present a measurement technique that uses the capabilities of the PEP-II programmable digital longitudinal feedback system to provide transient diagnostics in X or Y directions. This technique allows one to measure instability growth or damping rates as well as oscillation frequencies in both open-loop and closed-loop conditions. Based on these measurements the configuration of the relevant transverse feedback channel can be optimized. The technique will be illustrated with instability measurements and feedback optimization examples. Comparisons of the measured modal patterns and growth rates to the theoretical predictions will be presented.