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quadrupole

        
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MOP08 Investigation of the Beam Matching to the GSI-Alvarez DTL under Space Charge Conditions ion, emittance, space-charge, simulation 48
 
  • S. Yaramishev, W. Barth, L. Dahl, L. Groening, S. Richter
    GSI, Darmstadt
  The UNILAC consists of the 36 MHz high current RFQ/IH-injector, a gas stripper section at an energy of 1.4 MeV/u and a 108 MHz Alvarez poststripper, accelerating all ions up to of 11.4 MeV/u. The design beam current for U28+ is 12.6 emA at full energy. After the stripping process the electrical beam current is increased by a factor of 7 for uranium. This leads to a significant beam emittance growth during the transport through the charge state separator and the matching section to the Alvarez DTL. The paper reports results of beam experiments focused on the matching of the high intensity beams to the Alvarez for different ion species. Measured data are compared with the results of beam dynamics simulations. Possible improvements of the transverse focusing in the Alvarez linac are discussed and the total impact to the beam quality at the synchrotron injection is evaluated.  
Transparencies
 
MOP09 Status of the 7 MeV/u, 217 MHz Injector Linac for the Heidelberg Cancer Therapy Facility ion, linac, rfq, ion-source 51
 
  • B. Schlitt, K. Dermati, G. Hutter, F. Klos, C. Mühle, W. Vinzenz, C. Will, O. Zurkan
    GSI, Darmstadt
  • A. Bechtold, U. Ratzinger, A. Schempp
    IAP, Frankfurt-am-Main
  • Y.R. Lu
    PKU/IHIP, Beijing
  A clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) is under construction and will be installed at the Radiologische Universitätsklinik in Heidelberg, Germany, starting in 2005. The status of the ECR ion source systems, the beam line components of the low energy beam transport lines, the 400 keV/u RFQ and the 20 MV IH-cavity as well as the linac rf system will be reported. Two prototype magnets of the linac quadrupole magnets have been built at GSI and have been tested successfully. A test bench for the 1.4 MW, 217 MHz cavity amplifier built by industry has been installed at GSI including a 120 kW driver amplifier which will be used also for high power tests of the RFQ. A test bench for the RFQ using proton beams is presently being set up at the IAP. RF tuning of the 1:2 scaled IH-DTL model as well as Microwave Studio simulations of the model and the power cavity have been also performed at the IAP [1].

[1] Y.Lu, S.Minaev, U.Ratzinger, B.Schlitt, R.Tiede, this conference.

 
Transparencies
 
MOP12 KONUS Beam Dynamics Design of a 70 mA, 70 MeV Proton CH-DTL for GSI-SIS12 linac, proton, rfq, acceleration 60
 
  • R. Tiede, G. Clemente, H. Podlech, U. Ratzinger
    IAP, Frankfurt-am-Main
  • W. Barth, L. Groening
    GSI, Darmstadt
  • Z. Li
    IMP, Lanzhou
  • S. Minaev
    ITEP, Moscow
  The future scientific program at GSI needs a dedicated proton injector into the synchrotron SIS, in order to increase the proton intensity of the existing UNILAC/SIS12 combination by a factor of 70, resulting in 7· 1012 protons in the synchrotron. A compact and efficient 352 MHz RFQ - CH-DTL combination based on novel structure developments for RFQ and DTL was worked out. For DTLs operated in an H-mode like CH-cavities (H210-mode), the shunt impedance is optimized by use of the KONUS beam dynamics. Beam dynamics simulation results of the CH-DTL section, covering the energy range from 3 to 70 MeV, with emphasis on the low energy front end are presented. Optimization aims are the reduction of emittance growth, of beam losses and of capital costs, by making use of the high acceleration gradients and shunt impedance values provided by the Crossbar H-Type (CH) structure. In addition, the beam dynamics design of the overall DTL layout has to be matched to the power limits of the available 352 MHz power klystrons. The aim is to power each cavity by one klystron with a peak rf power of around 1 MW.  
 
MOP16 The TRASCO-SPES RFQ rfq, vacuum, dipole, coupling 69
 
  • A. Pisent, M. Comunian, J. Esposito, A. Palmieri
    INFN/LNL, Legnaro, Padova
  • E. Fagotti
    INFN Milano, Milano
  • G. Lamanna
    CINEL, Vigonza (PD)
  • M. S. Mathot
    CERN, Geneva
  A high intensity RFQ is under construction at LNL. Developed within TRASCO research program, the Italian feasibility study an ADS (Accelerator Driven System), it will be employed as the first accelerating element of SPES facility, the ISOL project of LNL. The RFQ operates at the frequency of 352 MHz in CW mode, is able to deliver a proton current up to 30 mA and consists of six brazed segments whose length is 1.2 m. In this article the results obtained from the construction of a 20 cm “technological model”, aimed at testing the construction procedure of the final structure, will be discussed. Finally we will report about the machining and the outcomes obtained after RF testing of the first two segments built up to now.  
 
MOP47 Limiting Effects in the Round-To-Flat Beam Transformation emittance, simulation, chromatic-effects, gun 150
 
  • Y.-E. Sun, K.-J. Kim
    Chicago University, Chicago, Illinois
  • P. Piot
    FNAL, Batavia, Illinois
  The transformation of an angular-momentum-dominated beam into a flat beam was analyzed in Ref. [K.-J. Kim, Phys. rev. ST A&B, vol 6, 104002 (2003)]. The analysis was performed assuming that the beam and the transport channel upstream of the flat beam transformer are cylindrically symmetric and that the particle dynamics is symplectic. We extend the analysis to include chromatic and space-charge effects as well as asymmetries in the four dimensional transverse phase space distribution.  
 
MOP66 Calculation of RF Properties of the Third Harmonic Cavity dipole, scattering, coupling, higher-order-mode 171
 
  • K. Rothemund, D. Hecht, U. van Rienen
    Rostock University, Faculty of Engineering, Rostock
  Recently a third harmonic structure has been proposed for the injector of the TTF-FEL to avoid nonlinear distortions in the longitudinal phase space. This structure, consists of four nine cell TESLA-like cavities. For the use of this structure in combination with the TTF-FEL it might be interesting to investigate higher order modes (HOM) in the structure and their effect on the beam dynamics. The complexity of the structure, four nine cell cavities assembled with four input couplers and eight HOM-couplers, results in an extremely high numerical effort for full 3D modelling. Therefor Coupled S-Parameter Calculation (CSC) [1] has been applied. This method is based on the scattering parameter description of the rf components found with field solving codes or analytically for components of special symmetry. This paper presents the results of the calculation of rf properties (e.g. scattering parameters, Q-values) of the complete four times nine cell structure equipped with all input- and HOM-couplers.

[1] H.-W. Glock, K. Rothemund, U. van Rienen, CSC - A Procedure for Coupled S-Parameter Calculations, IEEE Trans. Magnetics, vol. 38, pp. 1173 - 1176, March 2002

 
 
TUP01 RFQ Drift-Tube Proton Linacs in IHEP focusing, rfq, linac, emittance 285
 
  • Yu. Budanov, O.K. Belyaev, S.V. Ivanov, A.P. Maltsev, I.G. Maltsev, V.B. Stepanov, S.A. Strekalovskyh, V.A. Teplyakov, V. Zenin
    IHEP Protvino, Protvino, Moscow Region
  A linac with drift tubes and RF quadrupoles (alias, an RFQ DTL) constitutes a natural extension of the RFQ concept towards higher beam energies. Complementing an RFQ with drift tubes intermitted by spacer electrodes separates functions of focusing and acceleration. Such a structure allows for an increased accelerating rate and upgrades shunt impedance to values competitive against those inherent in the other common accelerator types. Various accelerating/focusing structures for the RFQ DTLs were implemented in IHEP. Their succession is marked by a progress in performance, which is due to efforts in design, manufacturing technology and calculation technique advances that facilitated R&D of such the structures. A sound practical expertise in the field is accumulated. The 30 MeV RFQ DTL is in service as an injector for a 1.5 GeV PS of IHEP since 1985. An upgraded successor – the RFQ DTL, employing a cavity loaded by a novel accelerating/focusing structure with an increased accelerating rate, is now being assembled and tested. Its pre-commissioning results will be outlined. Prospects in R&D of a structure suitable for a front-end part of the CERN SPL will be evaluated.  
Transparencies
 
TUP02 Development of a 352 MHz Cell-Coupled Drift Tube Linac Prototype coupling, linac, focusing, alignment 288
 
  • M. Vretenar, Y. Cuvet, J. Genest, C. Völlinger
    CERN, Geneva
  • F. Gerigk
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  At linac energies above 40 MeV, alternative structures to the conventional Drift Tube Linac can be used to increase efficiency and to simplify construction and alignment. In the frame of the R&D activities for the CERN SPL and Linac4, a prototype of Cell-Coupled Drift Tube Linac (CCDTL) at 352 MHz has been designed and built. This particular CCDTL concept is intended to cover the energy range from 40 to 90 MeV and consists of modules of ~5 m length made of 3 or 4-gap DTL tanks linked by coupling cells. The focusing quadrupoles are placed between tanks, and are aligned independently from the RF structure. The CCDTL prototype consists of two half tanks connected by a coupling cell and requires an RF power of 120 kW to achieve the design gradient. RF tests will be made at low and high power, the latter up to a 20% duty cycle. This paper introduces the main features of this CCDTL design, describes the RF and mechanical design of the prototype and presents the first measurement results.  
 
TUP03 Design of the LINAC4, A New Injector for the CERN Booster linac, rfq, proton, injection 291
 
  • M. Vretenar, R. Garoby, K. Hanke, A.M. Lombardi, C. Rossi
    CERN, Geneva
  • F. Gerigk
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  A new H- linac (LINAC4) is presently under study at CERN. This accelerator, based on normal conducting structures at 352 and 704 MHz, will provide a 40 mA 160MeV H- beam to the CERN booster, thus overcoming the present space-charge bottleneck at injection with a 50 MeV proton beam. LINAC4 is conceived as the first stage of a future 2.2 GeV superconducting linac (SPL) and it is therefore designed for a higher duty cycle than required for injection in the booster. This paper discusses the design choices, presents the layout of the facility and illustrates the advantages for the LHC and other CERN users. An R&D and construction strategy mainly relying upon international collaborations is also presented.  
 
TUP04 The SPL Front End: A 3 MeV H- Test Stand at CERN linac, rfq, proton, simulation 294
 
  • R. Garoby, L. Bruno, F. Caspers, J. Genest, K. Hanke, M. Hori, D. Kuchler, A.M. Lombardi, M. Magistris, A. Millich, M. Paoluzzi, C. Rossi, E.Zh. Sargsyan, M. Silari, T. Steiner, M. Vretenar
    CERN, Geneva
  • P.-Y. Beauvais
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  In the frame of the SPL (Superconducting Proton Linac) study at CERN, a new 160 MeV proton injector for the CERN PS Booster is presently under development. This linear accelerator (Linac4) would not only be a first step towards a future, multi-MW superconducting linac, but would also improve in the medium term both the beam availability and beam quality for CERN’s proton users. Within the framework of the Linac 4 study and with the support of the EU funded Joint Research Activity HIPPI*, a 3 MeV test stand is under construction at CERN. This test stand will explore some of the most critical issues of the linac, such as the beam dynamics at low energy, with special emphasis on the Chopper line that has been designed to generate the required time structure of the beam, to clean the beam halo, and to match it to the subsequent RF structures. In this context, a new Beam Shape and Halo Monitor is under construction. The beam acceleration will be performed by an RFQ that is being developed in France within the IPHI collaboration between CEA and CNRS. Moreover, the test stand will be equipped with an additional 1 MW RF klystron to test different RF structures that are being designed at 352 MHz as preliminary studies for the Linac4.

*High Intensity Pulsed Proton Injectors

 
Transparencies
 
TUP05 Beam Dynamics for a new 160 MeV H- Linac at CERN (LINAC4) linac, emittance, rfq, simulation 297
 
  • F. Gerigk
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  • E. Benedico Mora, A.M. Lombardi, E.Zh. Sargsyan, M. Vretenar
    CERN, Geneva
  LINAC4 is a normal conducting H- linac proposed at CERN to provide a higher proton flux to the CERN accelerator chain. It should replace the existing LINAC2 as injector for the PS booster. The same machine can also operate in the future as the front end of the SPL, a 2.2 GeV superconducting linac with 1.8 mA average current. At present the test set-up for LINAC4 consists of a Radio Frequency Quadrupole (RFQ), a chopper line, a Drift Tube Linac (DTL), and Cell Coupled DTL (CCDTL) operating at 352.2 MHz and finally a Side Coupled Linac (SCL) at 702.2 MHz. This paper discusses the overall beam dynamics concept, presents the optics for the different sections of the machine and compares end-to-end simulations realised with two tracking codes (PATH and IMPACT). Estimates of beam loss due to various error sources are presented and the challenging features in the current design are highlighted.  
Transparencies
 
TUP06 Results of the High-Power Conditioning and the First Beam Acceleration of the DTL-1 for J-PARC coupling, linac, rfq, acceleration 300
 
  • F. Naito, S. Anami, J. Chiba, Y. Fukui, K. Furukawa, Z. Igarashi, K. Ikegami, M. Ikegami, E. Kadokura, N. Kamikubota, T. Kato, M. Kawamura, H. Kobayashi, C. Kubota, E. Takasaki, H. Tanaka, S. Yamaguchi, K. Yoshino
    KEK, Ibaraki
  • K. Hasegawa, Y. Kondo, A. Ueno
    JAERI, Ibaraki-ken
  • T. Itou, Y. Yamazaki
    JAERI/LINAC, Ibaraki-ken
  • T. Kobayashi
    J-PARC, Ibaraki-ken
  The first tank of the DTL for Japan Proton Accelerator Research Complex (J-PARC) was installed in the test facility at KEK. The DTL tank is 9.9 m in length and consists of the 76 cells. The resonant frequency of the tank is 324 MHz. After the installation of the tank, the high-power conditioning was carried out deliberately. Consequently the peak rf power of 1.3 MW (pulse repetition 50 Hz, pulse length 600 μs) was put into the tank stably. (The required power is about 1.1 MW for the designed accelerating field of 2.5 MV/m on the axis.) Following the conditioning, negative hydrogen beam, accelerated by the RFQ linac up to 3 MeV, was injected to the DTL and accelerated up to its design value of 19.7 MeV. The peak current of 30 mA was achieved with almost 100% transmission. In this paper, the conditioning history of the DTL and the result of the first beam test will be described.  
 
TUP14 Status of the RFI Linac Prototype linac, rfq, ion, ion-source 321
 
  • D.A. Swenson, W.J. Starling
    LLC, Albuquerque, New Mexico
  A prototype of the Rf Focused Interdigital (RFI) linac structure is currently under construction at Linac Systems. The RFI linac structure is basically an interdigital (or Wideröe) linac structure with rf quadrupole focusing incorporated into each drift tube. The 200 MHz RFI prototype, consisting of a short RFQ linac followed by a short RFI linac, will accelerate a 20 mA beam of protons from an injection energy of 25 keV to an output energy of 2.50 MeV in a total linac structure length of 1.44 meters. The linac structures are designed for continuous (cw) operation, and will be tested initially at a 33% duty factor. The peak structure power of 66 kW and peak beam power of 50 kW will be supplied by a 144 kW, 33% duty rf power system. A microwave ion source will supply the proton beam and an articulated Einzel lens will steer and focus the beam into the RFQ aperture. The mechanical design of the linac structures will be presented, the calculated performance will be described, the status of the components will be reported. The prototype is scheduled to come into operation in the fall of this year.  
 
TUP18 Beam Dynamics Issues of SPES-1 Linac linac, simulation, rfq, emittance 330
 
  • E. Fagotti
    INFN Milano, Milano
  • M. Comunian, A. Palmieri, A. Pisent
    INFN/LNL, Legnaro, Padova
  An Independent Superconducting Cavity Linac able to accelerate 10 mA CW proton beam up to 20 MeV has been studied for the SPES-1 project. This paper presents the results of beam dynamics studies through SPES linac including mapped fields effects on cavities and magnets.  
 
TUP42 Beam Optics Studies for the TESLA Test Facility Linac undulator, optics, focusing, linac 360
 
  • P. Castro, V. Balandin, N. Golubeva
    DESY, Hamburg
  The aim of the TESLA Test Facility Linac is to create electron bunches of small transverse emittance and high peak current with energies up to 1 GeV for the VUV-FEL at DESY. The linac consists of a RF photo-cathode gun, a superconducting linac, two magnetic chicanes (for bunch compression), a long undulator magnet section and a beam line bypassing the undulator (for commissioning purposes). A study of (linear) beam optics of the linac is presented for the case of beam commissioning (and beam measurements), FEL operation and long bunch train operation. The requirements of each part of the linac upon the optics are discussed in detail and an appropriate solution for each case is shown, as well as the matching solution to the rest of the accelerator. The chromatic properties of the linac have been studied also.  
 
TUP48 Progress Report on the Flat Beam Experiment at the Fermilab/Nicadd Photoinjector Laboratory laser, emittance, simulation, cathode 378
 
  • Y.-E. Sun, K.-J. Kim
    Chicago University, Chicago, Illinois
  • N. Barov
    Northern Illinois University, DeKalb, Illinois
  • K. Desler
    DESY, Hamburg
  • H. Edwards, P. Piot, J. Santucci, J. Wennerberg
    FNAL, Batavia, Illinois
  • M. Huening
    Fermilab, Batavia, Illinois
  • S. Lidia
    LBNL/AFR, Berkeley, California
  • R. Tikhoplav
    Rochester University, Rochester, New York
  We report on our present progress toward the investigation on the generation of flat beam from an incoming angular-momentum-dominated beam, along with the associated diagnostics development. We focus on the evolution of the four-dimensional beam matrix upstream and downstream of the round-to-flat beam transformer. Finally we compare our latest experimental results with numerical and analytical models.  
 
TUP61 Beam Analysis Using the IPNS Linac ESEM linac, diagnostics, synchrotron, target 405
 
  • J.C. Dooling, F. R. Brumwell, L. Donley, G.E. McMichael, V. F. Stipp
    ANL, Argonne, Illinois
  The Energy Spread and Energy Monitor (ESEM) is an on-line, non-intrusive diagnostic used to characterize the output beam from the 200 MHz, 50 MeV linac. The energy spread is determined from a 3-size, longitudinal emittance measurement and energy is derived from TOF analysis. Presently, a single particle distribution is used to yield energy and energy-spread results. Effort is on-going to allow for more realistic distributions to be included. Signals are detected on terminated 50 Ω, stripline BPMs. Each BPM is constructed with four striplines: top, bottom, left and right. Until recently, the ESEM signals were taken solely from bottom striplines in four separate BPM locations in the transport line between the linac and synchrotron. We have begun to use the top stripline data to examine, in more detail, beam position and attempt to measure beam size. The electrostatic coupling between the stripline and the beam depends on the capacitance, which in turn is inversely related to the beam-stripline separation. The electrostatic portion of fluctuations in beam motion will be nonlinear, possibly allowing one to infer beam size.  
 
TUP67 Beam-Based Alignment Measurements of the LANSCE Linac injection, focusing, lattice, linac 420
 
  • R.C. McCrady, L. Rybarcyk
    LANL, Los Alamos, New Mexico
  We have made measurements of the alignment of the LANSCE Drift Tube linac (DTL) and Side Coupled linac (SCL) using beam position measurements and analyzing them with linear models. In the DTL, we varied the injection steering, measured the beam position after each DTL tank, and analyzed the data with a linear model using R-matrices that were computed by the Trace-3D computer program. The analysis model allowed for tank-to-tank misalignments. The measurements were made similarly in the SCL, where the analysis model allowed for misalignments of each quadrupole doublet lens. We present here the analysis techniques, the resulting alignment measurements and comparisons to measurements made with optical instruments.  
 
TUP69 Precision Alignments of Stripline BPMs with Quadrupole Magnets for TTF2 alignment, linac, synchrotron, pick-up 426
 
  • G. Priebe, D. Nölle, M. Wendt, M. Werner
    DESY, Hamburg
  We report on our alignment setup to calibrate beam position monitors (BPM) with respect to the magnetic axis of the quadrupole magnets used in the warm sections of the TESLA Test Facility (TTF2). The Stripline BPM's are fixed inside the quadrupole magnets. A streched wire measurement was used to calibrate the electrical axis of the BPM wrt. to the magnetic axis of the quadrupole.  
 
TUP70 Systematic Calibration of Beam Position Monitor in the High Intensity Proton Accelerator (J-PARC) LINAC pick-up, linac, simulation, proton 429
 
  • S. Sato, K. Hasegawa, F. Hiroki, J. Kishiro, Y. Kondo, M. Tanaka, T. Tomisawa, A. Ueno, H. Yoshikawa
    JAERI, Ibaraki-ken
  • Z. Igarashi, M. Ikegami, N. Kamikubota, S. Lee, K. Nigorikawa, T. Toyama
    KEK, Ibaraki
  In J-PARC, a MW class of proton accelerator is under construction. Improperly- tuned beam would critically result in unacceptable (>0.1%) energy loss. Systematic strategy of fine calibrations of the beam position monitor (BPM) detectors, is therefore required. First, Off-beam-line calibrations of BPMs are taken, with a dedicatedly- designed bench, which has a beam-simulating electric wire carrying 324 MHz. And then discrepancies are calibrated for each BPM between reconstructed electrical center of pick-up plates and measured mechanical center, before the installation of BPM on the beam line. Secondly, after BPMs are installed on the beam line, real beam is used for systematic calibrations (Beam Based Calibration (BBC)). The discrepancies are calibrated between electromagnetic center of Q-magnets and reconstructed beam position. In KEK we have the first stage of J-Parc LINAC with Ion source, RFQ, DTL, Q- and steering-magnets, and lots of BPMs. Implementation of BBC is going with SAD-language, which can also be used for beam steering and beam trajectory simulations, e.g. TRACE-3D. In this presentation, such strategic BPM calibration system will be intensively described.  
 
TUP74 The Beam Diagnostics System in the J-PARC LINAC linac, beam-losses, radiation, diagnostics 441
 
  • S. Lee, Z. Igarashi, T. Toyama
    KEK, Ibaraki
  • H. Akikawa
    JAERI/LINAC, Ibaraki-ken
  • F. Hiroki, J. Kishiro, S. Sato, M. Tanaka, T. Tomisawa
    JAERI, Ibaraki-ken
  • H. Yoshikawa
    JAERI/FEL, Ibaraki-ken
  Large amount of beam monitors will be installed in J-PARC linac. Electrostatic computations are used to adjust the BPM cross-section parameters to obtain 50 Ω transmission lines. BPMs are designed to control the offset between quadrupole magnet and BPM electrical centers less than 0.1mm. We present a procedure of beam based calibration/alignment (BBC/BBA) method to confirm the displacement of linac BPMs. The fast current transformer (FCT) has response of relative bunch phase <1%. To measure the beam energy at every accelerator tank and injection point of 3 GeV RCS, phase difference of FCT pairs are used, and 10-4 order energy resolutions can be expected. The loss monitor system (BLM) is composed of scintillator and Ar-CH4/CO2 gas filled proportional counter. To prevent the activation and heat load by intense beam loss, fast time response of loss signals is required. Profile measurements can also be used to determine the beam emittance of a matched beam in a periodic focusing lattice. The thin sensing wire scanner (WS) has been designed to obtain a current density distribution of the beam. This paper describes the instruments and R&D result of beam monitors in J-PARC linac.  
 
TUP81 Superstrong Adjustable Permanent Magnet for a Linear Collider Final Focus permanent-magnet, linear-collider, collider, multipole 462
 
  • Y. Iwashita, T. Mihara
    Kyoto ICR, Kyoto
  • A. Evgeny, M. Kumada
    NIRS, Chiba-shi
  • C. M. Spencer
    SLAC, Menlo Park, California
  • E. Sugiyama
    NEOMAX, Osaka
  Super-strong permanent magnets are being considered as one of the candidates for the final focus quadrupole magnets in a linear collider. A short prototype with temperature compensation included and variable strength capability has been designed and fabricated. Fabrication details and some magnetic measurement results will be presented.  
Transparencies
 
TUP84 Spectrographic Approach to Study of RF Conditioning Process in Accelerating RF Structures RF-structure, plasma, vacuum, electron 471
 
  • H. Tomizawa, H. Hanaki, T.  Taniuchi
    JASRI-SPring-8, Hyogo
  • A. Enomoto, Y. Igarashi, S. Yamaguchi
    KEK, Ibaraki
  The acceleration gradient of a linac is limited by rf breakdown in its accelerating structure. We applied an imaging spectrograph system to study the mechanism of rf breakdown phenomena in accelerating rf structures. Excited outgases emit light during rf breakdown, and the type of outgases depend on surface treatments and rinsing methods for their materials. To study rf breakdown, we used 2-m-long accelerating structures and investigated the effects when high-pressure ultrapure water rinsing (HPR) treatment was applied to these rf structures. We performed experiments to study the outgases under rf conditioning with quadruple mass spectroscopy and imaging spectrography. As a result, we could observe instantly increasing signals at mass numbers of 2 (H2), 28 (CO), and 44 (CO2), but not 18 (H2O) just after the rf breakdown. We also conducted spectral imaging for the light emissions from the atoms in a vacuum that are excited by rf breakdown. Without HPR, we observed the atomic lines at 511 nm (Cu I), 622 nm (Cu II), and 711 nm (C I). With HPR, 395 nm (O I), 459 nm (O II), 511 nm (Cu I), 538 nm (C I), 570 nm (Cu I), 578 nm (Cu I), 656 nm (H I), and 740 nm (Cu II) were observed.  
 
TUP85 J-PARC Linac Alignment alignment, linac, beam-transport, monitoring 474
 
  • M. Ikegami, C. Kubota, F. Naito, E. Takasaki, H. Tanaka, K. Yoshino
    KEK, Ibaraki
  • H. Ao, T. Itou
    JAERI/LINAC, Ibaraki-ken
  • K. Hasegawa, T. Morishita, N. Nakamura, A. Ueno
    JAERI, Ibaraki-ken
  J-PARC linac consists of a 3 MeV RFQ linac, a 50 MeV DTL (Drift Tube Linac), a 190 MeV SDTL (Separate-type DTL), and a 400 MeV ACS (Annular-Coupled Structure) linac, and its total length is more than 400 m including the beam transport line to the succeeding RCS (Rapid Cycling Synchrotron). In high-current proton accelerators, precise alignment of accelerator components is indispensable to reduce uncontrolled beam loss and beam quality deterioration. In this paper, planned schemes for the linac alignment is presented together with instrumentation for the long-term ground-motion watching.  
 
TUP86 Coupler Development and Gap Field Analysis for the 352 MHz Superconducting CH-Cavity coupling, linac, simulation, proton 477
 
  • H. Liebermann, H. Podlech, U. Ratzinger, A.C. Sauer
    IAP, Frankfurt-am-Main
  The cross-bar H-type (CH) cavity is a multi-gap drift tube structure based on the H-210 mode currently under development at IAP Frankfurt and in collaboration with GSI. Numerical simulations and rf model measurements showed that the CH-type cavity is an excellent candidate to realize s.c. multi-cell structures ranging from the RFQ exit energy up to the injection energy into elliptical multi-cell cavities. The reasonable frequency range is from about 150 MHz up to 800 MHz. A 19-cell, β=0.1, 352 MHz, bulk niobium prototype cavity is under development at the ACCEL-Company, Bergisch-Gladbach. This paper will present detailed MicroWave Studio simulations and measurements for the coupler development of the 352 MHz superconducting CH cavity. It will describe possibilities for coupling into the superconducting CH-Cavity. The development of the coupler is supported by measurement on a room temperature CH-copper model. We will present the first results of the measurements of different couplers, e.g. capacitive and inductive couplers, at different places of the CH Cavity.  
 
TUP87 Technologies of The Peripheral Equipments of The J-PARC DTL1 for the Beam Test power-supply, site, linac, proton 480
 
  • K. Yoshino, Y. Fukui, E. Kadokura, T. Kato, C. Kubota, F. Naito, E. Takasaki, H. Tanaka
    KEK, Ibaraki
  • T. Itou
    JAERI/LINAC, Ibaraki-ken
  First beam test of the DTL1 was performed in November of 2003 at KEK site. A 30 mA H- beam was successfully accelerated from 3 to 19.7 MeV. In order to prepare the beam test, various peripheral equipments were developed: the electrode plates for connecting the hollow-conductor coil and the power cable were developed since quadrupole electromagnets are built in all DTs (77 sets) of the DTL1, the water-cooled multiconductor copper tube (Control Copper Tube) were used as the power cable from the electrode plate to power supply, and the interlock system assembled by PLCs (Programmable Logic Controller) was also prepared for the surveillance of many cooling channel.  
 
TUP88 CLIC Magnet Stabilization Studies linac, luminosity, site, collider 483
 
  • S. Redaelli, R.W. Assmann, W. Coosemans, G. Guignard, D. Schulte, I. Wilson, F. Zimmermann
    CERN, Geneva
  One of the main challenges for future linear colliders is producing and colliding high energy e+e- beams with transverse spot sizes at the collision point in the nanometre range. Preserving small emittances along several kilometres of linac requires the lattice quadrupoles to be stable to the nanometre level. Even tighter requirements are imposed on the stability of the final focus quadrupoles, which have to be stable to a fraction of the colliding beam size to reliably steer the opposing beams in collision. The Compact LInear Collider (CLIC), presently under investigation at CERN, aims at colliding e+e- beams with a vertical spot size of 0.7 nm, at a centre-of-mass energy of 3 TeV. This requires a vertical stability to the 1.3 nm level for the 2600 linac quadrupoles and to the 0.2 nm level for the two final focus quadrupoles. The CLIC Stability Study has demonstrated for the first time that CLIC prototype quadrupoles can be stabilized to the 0.5 nm level in a normal working area on the CERN site. Detailed tracking simulations show that with this level of stability, approximately 70% of the CLIC design luminosity would be achieved. This paper summarizes the work and the achievements of the CLIC Stability Study.  
Transparencies
 
THP14 High Beta Cavity Optimization for ISAC-II linac, ion, acceleration, emittance 627
 
  • R.E. Laxdal, V. Zvyagintsev
    TRIUMF, Vancouver
  • Z.H. Peng
    CIAE, Beijing
  The linac for ISAC-II comprises twenty cavities of medium beta (β=5.8 and 7.1%) quarter wave cavities now in the installation phase. A second stage will see the installation of ~20 MV of high beta quarter wave cavities (~10.4%). The cavity structure choice depends on the efficiency of operation, cost, stability, beam dynamics and schedule. Two main cavity types are considered; a low frequency 106 MHz option and a high frequency 141 MHz cavity. We compare and contrast the cavity choices.  
 
THP17 Progress in the Development of the TOP Linac linac, proton, booster, impedance 633
 
  • L. Picardi, C. Ronsivalle
    ENEA C.R. Frascati, Frascati (Roma)
  • S. Frullani
    ISS, Rome
  The TOP Linac (Oncological Therapy with Protons), under development by ENEA and ISS is a sequence of three pulsed (5 msec, 300 Hz) linear accelerators: a 7 MeV, 425 MHz RFQ+DTL (AccSys Model PL-7), a 7–65 MeV, 2998 MHz Side Coupled Drift Tube Linac (SCDTL) and a 65–200 MeV, variable energy 2998 MHz Side Coupled Linac (SCL). The first SCDTL module is composed by 11 DTL tanks coupled by 10 side cavities. The tanks has modified to overcome vacuum leakage that occurred during brazing, and now the module has been completed, and is ready to be tested with protons. The 7 MeV injector has been recently installed in the ENEA Frascati laboratories for preliminary test, before being transferred to the main Oncologycal Hospital in Rome, Istituto Regina Elena.  
Transparencies
 
THP21 Calculation of Electron Beam Dynamics of the LUE-200 Accelerator electron, focusing, target, simulation 639
 
  • A.P. Sumbaev, V. Alexandrov, N.Y. Kazarinov, V.F. Shevtsov
    JINR, Dubna, Moscow Region
  The results of calculations of the focusing and transportation systems of the electron beam of LUE-200 accelerator – the driver of a pulse source of resonant neutrons IREN, JINR (Dubna), are presented. Simulations of the beam dynamics in the traveling wave accelerator were carried out by means of PARMELA code. The calculations have been fulfilled for various parameters of the focusing magnetic fields in the accelerator and the channel, various currents of the beam and various initial distributions of electrons.  
 
THP89 Measured RF Properties of the DTL for the J-PARC insertion, linac, target, synchrotron 809
 
  • H. Tanaka, T. Kato, F. Naito, E. Takasaki
    KEK, Ibaraki
  • H. Asano, T. Morishita
    JAERI, Ibaraki-ken
  • T. Itou
    JAERI/LINAC, Ibaraki-ken
  RF properties of the second DTL tank for J-PARC have been measured in KEK. The required flatness and stability of the accelerating field of the tank have been achieved by the tunung of the post-couplers, whose shape were modified to adjust the resonant frequency ?324 MHz). Because the third DTL tank has assembled, the rf measurement and the post-coupler tuning will be started soon. Thus the measured results for both tanks will be described in the paper.