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Paper Title Other Keywords Page
MO202 High-Intensity, High Charge-State Heavy Ion Sources electron, laser, ion-source, plasma 8
 
  • J. Alessi
    BNL, Upton, Long Island, New York
  There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions will be reviewed. These sources include ECR, EBIS, and Laser ion sources. The benefits and limitations for these type sources will be described, for both dc and pulsed applications. Possible future improvements in these type sources will also be discussed.  
Transparencies
 
MO203 Non-Interfering Beam Diagnostic Developments electron, diagnostics, linac, proton 13
 
  • A. Peters, P. Forck
    GSI, Darmstadt
  New high power proton and heavy ion linac projects are a big challenge for beam diagnostic developments. Due to the high inherent beam power mostly all destructive measurement techniques are not applicable. Thus a lot of beam diagnostic developments are under way from enhancements of well-known systems like beam position pick-ups or current transformers to new designs for profile or bunch length measurements using e.g. the interaction of the high power beams with the residual gas in the linacs. The latest progress in this field will be reviewed with descriptions of some remarkable solutions.  
Transparencies
 
MO204 Status of REX-ISOLDE linac, emittance, injection, target 18
 
  • O.K. Kester, S. Emhofer, D. Habs, K. Rudolph
    LMU, Garching
  • F. Ames, P. Butler, P. Delahaye, M. Lindroos, T. Sieber, F.J.C. Wenander
    CERN, Geneva
  • R. Repnow, H. Scheit, D. Schwalm, R. von Hahn
    MPI-K, Heidelberg
  After commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) first series of physics experiments in 2002 and 2003 have been performed. The REX-ISOLDE charge state breeder adjusts the charge-to-mass ratio of isotopes from all over the nuclear chart to the LINAC requirements. A variety of isotopes from different mass regions of the nuclear chart have been charge bred with REXEBIS to the required A/q < 4.5. A variety of tests with REXTRAP, REXEBIS and the LINAC structures have been done, in order to study the beam parameters, transmission efficiency and upgrade options. The LINAC now consists of six resonators and one re-buncher cavity. The beam energy, which can be delivered towards the target areas, can be varied between 0.8 and 2.2. An additional boost to 3 MeV/u is now possible because of the upgrade with a 202.56 MHz IH-cavity developed for the MAFF project. In addition experiment using beams from the RFQ at 0.3 MeV/u have been performed for solid state physics experiments. The present status of the projects and the commissioning measurements will be presented.  
Transparencies
 
MO301 SPIRAL2 at GANIL rfq, linac, emittance, ion-source 23
 
  • M.-H. Moscatello
    GANIL, Caen
  The detailed design study phase of the SPIRAL2 project has been launched since beginning of 2003. The aim of this facility is to produce rare ion beams, using a Uranium carbide target fission process, based on a fission rate of 1013 to 1014 fissions/s. The driver accelerator accelerates a 5 mA deuteron beam up to 20 MeV/u, impinging on a carbon converter to produce the neutrons necessary to the fission process. It has also to accelerate q/A=1/3 heavy ions, to energies between 0.75 and 14.5 MeV/A for different types of nuclear and non-nuclear physics experiments. The accelerator, based on a RFQ followed by an independently phased superconducting cavity linac with warm focusing sections, is under design. This paper presents the reference design chosen for SPIRAL2 driver accelerator and gives the design status of the different components: Sources, RFQ, Superconducting linac, RF Systems, Cryogenics, Mechanical layout.  
Transparencies
 
MO302 Development of Room Temperature and Superconducting CH-Structures linac, proton, impedance, acceleration 28
 
  • H. Podlech
    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 a large variety of applications in 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 H21 mode. Due to its mechanical stability, room temperature as well as superconducting cavities can be realized. The CH-structure is an excellent candidate for high power ion accelerators in the energy range from 5 to 100 MeV. The design status of the GSI 70 MeV, 70 mA proton injector DTL consisting of room temperature CH-structures is reported. Superconducting CH-structures can be used especially for cw operated linacs as designed for XADS, IFMIF or in nuclear physics projects. By using the KONUS beam dynamics and performing the particle simulations with the LORASR code it is possible to realize multi cell cavities without internal focusing lenses. A superconducting 352 MHz CH-structure (β=0.1) with 19 gaps has been built. We present the results of the first tests with this new cavity. The status of a PC version of the LORASR code will be reported.  
Transparencies
 
MOP01 Beam Intensity Adjustment in the RIA Driver Linac target, linac, focusing, impedance 33
 
  • P.N. Ostroumov, J.A. Nolen, I. Sharamentov
    ANL/Phys, Argonne, Illinois
  • A.V. Novikov-Borodin
    RAS/INR, Moscow
  The Rare Isotope Accelerator Facility currently being designed in the U.S. will use both heavy ion and light ion beams to produce radionuclides via the fragmentation and spallation reactions, respectively. Driver beam power of up to 400 kW will be available so that beam sharing between target stations is a viable option to increase the number of simultaneous users. Using a combination of rf-sweepers and DC magnets the driver beams can be delivered to up to four targets simultaneously. With simultaneous beam delivery to more than one target independent adjustment of the relative beam intensities is essential. To enable such intensity adjustment we propose to use a fast chopper in the Medium Energy Beam Transport (MEBT) section. Several options of fast chopper design are discussed. The MEBT beam optics is being designed to accommodate and match the chopper technical specifications. Possible solutions and performance with the fast chopper are proposed.  
 
MOP05 The HITRAP-Decelerator for Heavy Highly-Charged Ions rfq, extraction, emittance, storage-ring 39
 
  • L. Dahl, W. Barth, T. Beier, W. Vinzenz
    GSI, Darmstadt
  • C. A. Kitegi, U. Ratzinger, A. Schempp
    IAP, Frankfurt-am-Main
  The GSI accelerator facility provides highly charged ions up to U92+ by stripping the ions at 400 MeV/u in the transfer line from the SIS18 (Heavy Ion Synchrotron) to the ESR (Experimental Storage Ring). The ESR provides high quality beams by means of stochastic cooling and electron cooling. Deceleration down to 4 MeV/u was already successfully demonstrated. After suitable rebunching, further deceleration down to 6 keV/u, neccessary for the capture of the ions by a penning trap, is done by IH/RFQ-structures. All cavities are operated at 108 MHz. Recently the HITRAP-project (Heavy Ion Trap), described in a Technical Design Report, was approved. The layout of the decelerator and the beam dynamics in different sections are reported.  
 
MOP06 A Dedicated 70 MeV Proton Linac for the Antiproton Physics Program of the Future Facility for Antiproton and Ion Research (FAIR) at Darmstadt proton, linac, rfq, antiproton 42
 
  • L. Groening, W. Barth, L. Dahl, R. Hollinger, P. Spädtke, W. Vinzenz, S. Yaramishev
    GSI, Darmstadt
  • B. Hofmann, Z. Li, U. Ratzinger, A. Schempp, R. Tiede
    IAP, Frankfurt-am-Main
  The antiproton physics program of the future International Accelerator Facility at Darmstadt is based on a rate of 7·1010 cooled antiprotons per hour. To provide the primary proton intensities a proton linac is planned, which will be operated independently from the existing UNILAC for heavy ions. The proposed linac comprises a proton source, a RFQ, and a DTL. Its operation frequency of 352 MHz allows for an efficient acceleration to up to 70 MeV using normal conducting Crossed-bar H-cavities. These CH-cavities show high shunt impedances as known from IH-structures, but allow for much higher relative particle velocities of up to 40%. The beam pulses with a length of 25 μs, a current of 70 mA, and total transverse emittances of 7 μm will allow to fill the existing synchrotron SIS within one multi-turn-injection up to its space charge limit of 7·1012 protons. The maximum SIS ramping rate limits the applied proton linac repetition rate to 5 Hz. This paper gives an overview of the proposed proton linac. The status of the design including beam dynamic studies will be reported.  
Transparencies
 
MOP07 High Current Beam Transport to SIS18 emittance, injection, simulation, space-charge 45
 
  • S. Richter, W. Barth, L. Dahl, J. Glatz, L. Groening, S. Yaramishev
    GSI, Darmstadt
  The optimized transversal and longitudinal matching of space charged dominated ion beams to SIS18 is essential for a loss free injection. This paper focuses on the beam dynamics in the transfer line (TK) from the post-stripper accelerator to the SIS18. Transverse beam emittance measurements at different positions along the TK were done. Especially, the different foil stripping modes were investigated. A longitudinal emittance measurement set-up was commissioned at the entry to the TK. It is used extensively to tune all the rebunchers along the UNILAC. An addition, a test bench is in use for measurements of longitudinal bunch profiles, which enables to monitor for the final debunching to SIS18. Multi particle simulations by means of PARMILA allow a detailed analysis of experimental results for different ion currents.  
 
MOP08 Investigation of the Beam Matching to the GSI-Alvarez DTL under Space Charge Conditions quadrupole, 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 linac, quadrupole, 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
 
MOP10 The IH Cavity for HITRAP emittance, rfq, bunching, simulation 54
 
  • C. A. Kitegi, U. Ratzinger
    IAP, Frankfurt-am-Main
  • S. Minaev
    ITEP, Moscow
  RFQs are already successfully used to decelerate ions and to match them to ion traps. Within the Heavy Ions TRAP project HITRAP at GSI a combination of an IH drift tube cavity operating at the H11(0) mode and a 4-rod RFQ is proposed to decelerate the 1 ms long heavy ion bunches (up to U92+) from 4 A×MeV to 6 A keV after storage ring extraction. The transition energy from the IH into the RFQ is 0.5AmeV. The operating frequency is 108.408 MHz. The A/q range of the linac is up to 3.A 4-gap quarter wave resonator working at 108.408MHz provides theμbunch structure for the IH. The transmission mainly defined by the buncher is about 30%. An alternative 2nd harmonic bunching section, which allows higher transmission and/or smaller longitudinal emittance, will be discussed.By applying the KONUS dynamics, the 2.7 meter long IH cavity will perform a high efficient deceleration by up 10.5 MV with 200kW rf power. The beam dynamics performed with the LORASR simulation code will be shown. It is aimed to reach an effective shunt impedance around 220MW/m for the IH cavity  
 
MOP11 The Compact 20 MV IH-DTL for the Heidelberg Cancer Therapy Facility simulation, rfq, linac, emittance 57
 
  • Y.R. Lu, Y.R. Lu, B. Schlitt
    GSI, Darmstadt
  • S. Minaev
    ITEP, Moscow
  • U. Ratzinger, R. Tiede
    IAP, Frankfurt-am-Main
  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 different rf tuning concepts and tuning results for an 1:2 scaled IH-DTL model cavity are presented. Microwave Studio simulations have been carried out for the model and for the real power cavity. Results from the model measurements and the field simulations agree very well also for the higher order modes. The beam matching from the RFQ to the IH-DTL was optimised. Beam dynamics simulations using the LORASR code and starting with a particle distribution at the RFQ exit as calculated with PARMTEQ are presented. The IH drift tube array was matched with the gap voltage distribution resulting from rf model measurements.  
 
MOP17 Design of the SPES-1 LEBT electron, rfq, simulation, proton 72
 
  • E. Fagotti
    INFN Milano, Milano
  • M. Comunian, A. Pisent
    INFN/LNL, Legnaro, Padova
  The low-energy-beam transport (LEBT) system for the SPES-1 accelerator transports the beam at 80 keV and 30 mA from the ion-source TRIPS to the TRASCO RFQ entrance. A second mode of operation corresponding to 10 mA current is also foreseen. The code PARMELA performed these simulations of the beam transport through the LEBT. This code is used to transport H+ and H2+ in the electrostatic fields of the ion-source extraction, in the magnetic fields of both the source and the solenoid lenses and under space charge and neutralization influence.  
 
MOP68 Ribbon Ion Beam Dynamics in Undulator Linear Accelerator focusing, undulator, acceleration, linac 177
 
  • E.S. Masunov, S.M. Polozov
    MEPhI, Moscow
  The possibility to use radio frequency undulator fields for ion beam focusing and acceleration in linac (UNDULAC-RF) is discussed. In periodical resonator structure the accelerating force is produced by the combination of two or more space harmonics of a longitudinal or a transverse undulator field*. The particle motion equations in Hamilton form are carried out by means of smooth approximation. The analysis of 3D effective potential permits to find the conditions under which focusing and acceleration of the particles occur simultaneously. The analytical results are verified with a numerical simulation. Examples illustrating the efficiency of the proposed method of acceleration are given for longitudinal and transverse undulators. The results are compared with a conventional linac and the other possibility of ion beam acceleration in UNDULAC-E(M) where electrostatic and magnetic fields are used.

*E.S. Masunov, Technical Physics, Vol. 46, No.11, 2001, pp. 1433-1436.

 
 
MOP74 Recent Results of the 2.45 GHz ECR Source Producing H- Ions at CEA/Saclay plasma, electron, ion-source, extraction 195
 
  • R. Gobin, K. Benmeziane, O. Delferriere, R. Ferdinand, F. Harrault
    CEA/DAPNIA-SACM, Gif-sur-Yvette Cedex
  • A. Girard
    CEA DSM Grenoble, Grenoble
  Low frequency ECR plasma sources have demonstrated their efficiency, reproducibility and long life time for the production of positive light ions. In 2003, the new 2.45 GHz ECR test stand based on a pure volume H- ion production, developed at CEA/Saclay, showed a dramatic increase of the H- extracted ion beam. In fact, a stainless steel grid now divides the plasma chamber in two different parts: the plasma generator zone and the negative ion production zone. By optimizing the grid position and its potential with respect to the plasma chamber, the negative ion current reached close to 1 mA. Ceramic plates, covering the plasma chamber walls help electron density and lead to an optimisation of the ion production. A 50 % improvement has been observed. A new 6 kW magnetron RF generator now replaces the 1.2 kW previous one and the current will be soon plotted versus the RF power. New Langmuir probe measurements are also expected on both sides of the grid. The last results will be reported and discussed.  
Transparencies
 
MOP76 Ultra-High-Vacuum Problem for 200 keV Polarized Electron Gun with NEA-GaAs Photocathode gun, emittance, electron, cathode 201
 
  • T. Nakanishi, F. Furuta, M. Kuwahara, K. Naniwa, S. Okumi, M. Yamamoto, N. Yamamoto, K. Yasui
    DOP Nagoya, Nagoya
  • H. Kobayakawa, Y. Takashima
    DOE Nagoya, Nagoya-City
  • M. Kuriki, H. Matsumoto, M. Yoshioka
    KEK, Ibaraki
  For a polarized electron source based on photoemission from GaAs, a NEA (Negative Electron Affinity) surface makes an indispensable role to extract polarized electrons in conduction band into vacuum. The NEA surface is also considered as a best surface to provide a beam with a minimum initial beam-emittance. However, the NEA surface state is realized by a mono-layer of electric dipole moment (that is Ga(-)-Cs(+)) formed at the surface and thus it is easily degraded by
  1. desorption of harmful residual gas,
  2. desorption of harmful gas created by field emission from HV-cathodes and
  3. ion back-bombardment.
In order to reduce the effects of (a) and (c), extremely good UHV is required. Presently total pressure of 4·10-12 torr and respective partial pressures of 3·10-13 torr and 4·10-13 torr for H2O and CO2 were achieved at our gun chamber. Field emission dark current must be extremely suppressed to reduce the effect of (c). The maximum field gradient of 7.8 MV/m is applied for electrode envelope (3.0 MV/m for cathode surface) at 200 kV DC bias-voltage, but total dark current was suppressed below 1 nA for our electrodes. The NEA lifetime under these conditions will be reported at the conference. 		 
 
MOP81 Analysis of the Qualification-Tests Performance of the Superconducting Cavities for the SNS Linac linac, simulation, radiation, electron 210
 
  • J. R. Delayen, J. Mammosser, O. Ozelis
    Jefferson Lab, Newport News, Virginia
  Thomas Jefferson National Accelerating Facility (Jefferson Lab) is producing superconducting radio frequency (SRF) cryomodules for the Spallation Neutron Source (SNS) cold linac. This consists of 11 medium-beta (β=0.61) cyomodules of 3 cavities each, and 12 high-beta (β=0.81) cryomodules of 4 cavities each. Before assembly into cavity strings the cavities undergo individual qualification tests in a vertical cryostat (VTA). In this paper we analyze the performance of the cavities during these qualification tests, and attempt to correlate this performance with cleaning, assembly, and testing procedures. We also compare VTA performance with performance in completed cryomodules.  
 
TU103 Development of the UNILAC Towards a Megawatt Beam Injector heavy-ion, linac, rfq, proton 246
 
  • W. Barth, L. Dahl, J. Glatz, L. Groening, S. Richter, S. Yaramishev
    GSI, Darmstadt
  For the future Facility for Antiproton and Ion Research (FAIR) at Darmstadt the present GSI-accelerator complex, consisting of the linear accelerator UNILAC and the heavy ion synchrotron SIS18, is foreseen to serve as an U28+ injector for up to 1012 particles/sec. After a new High Current Injector was installed, many different ion species were accelerated in the UNILAC for physics experiments. In 2001 a high energy physics experiment used up to 2·109 uranium ions per spill (U73+), while a MEVVA ion source was in routine operation for the first time. In the past two years different hardware measures and a careful fine tuning in all sections of the UNILAC resulted in an increase of the beam intensity to 9.5·1010 U27+ ions per 100 μs or 1.5·1010 U73+ ions per 100 μs. The contribution reports results of beam measurements during the high current operation with uranium beams (pulse beam power up to 0.5 MW). One of the major tasks was to optimize the beam matching to the Alvarez-DTL. In addition further upgrades, including improved beam diagnostics, are described, which allow to fill the SIS18 up to the space charge limit of 2.7·1011 U28+ ions per cycle.  
Transparencies
 
TU104 Developments and Future Plans at ISAC/TRIUMF target, ion-source, linac, cyclotron 251
 
  • P. Schmor
    TRIUMF, Vancouver
  The ISAC (Isotope Separator and Accelerator) at TRIUMF uses the ISOL (On Line Isotope Separator) technique with up to 100 microA of 500 MeV protons from the TRIUMF cyclotron driver to create exotic isotopes in a thick target. An ion beam formed from these exotic isotopes is transported at 2 keV/u, mass separated, injected into a room temperature RFQ Linac and then into a five-tank drift tube linac that provides variable-energy accelerated exotic-beams from 0.15 to 1.8 MeV/u for nuclear astrophysics experiments. Super conducting rf cavities are presently being added to the linac chain to permit a further increase in the maximum energy of the exotic beams to 6.5 MeV/u. An ECR-based charge state booster is also being added in front of the RFQ to increase the available mass range of the accelerated isotopes from 30 to about 150. A second proton beam line and new target station for target and ion source development have been proposed for ISAC. In the future this new target station could be used as an independent simultaneous source of exotic beams for the experimental program.  
Transparencies
 
TU301 High Power CW Superconducting Linacs for EURISOL and XADS linac, proton, cyclotron, target 275
 
  • J.-L. Biarrotte
    IPN, Orsay
  A multi-MW superconducting proton linac is proposed as the baseline solution for the EURISOL and the XADS driver accelerators. In the EURISOL project, which studies the design of the next-generation European ISOL facility, it is used to produce both neutron-deficient and neutron-rich exotic nuclei far from the valley of stability. In the PDS-XADS project, which aims to the demonstration of the feasibility of an ADS system for nuclear waste transmutation, it is used to produce the neutron flux required by the associated sub-critical reactor. In this paper, we report the main results and conclusions reached within these preliminary design studies. A special emphasis is given on the on-going and future R&D to be done to accomplish the demonstration of the full technology.  
Transparencies
 
TUP08 Carbon Ion Injector Linac for a Heavy Ion Medical Synchrotron linac, rfq, focusing, vacuum 306
 
  • D.A. Swenson
    LLC, Albuquerque, New Mexico
  The design of a Carbon Ion Injector Linac for a heavy ion medical synchrotron will be presented. The linac is designed to accelerate quadruply-ionized carbon ions (12C4+) with a charge/mass ratio (q/A) of 0.333, and all other ions with the same or higher charge/mass ratios, such as H1+, H21+, D1+, T1+, 3He1+, 4He2+, 6Li2+, 10B4+, and 16O6+ to an output energy of 7 MeV/u. The 200 MHz linac consists of an Radio Frequency Quadrupole (RFQ) linac to accelerate the ions from an input energy of 0.008 MeV/u to an intermediate energy of 0.800 MeV/u, and an Rf-Focused Interdigital (RFI) linac to accelerate these ions to the output energy. The combined linac structures have a total length of 7.8 meters and a total peak rf power requirement of about 600 kW. The RFQ linac employs a radial-strut, four-bar design that is about twice as efficient as the conventional four-bar RFQ design. The RFI linac, which is basically an interdigital drift tube structure with rf quadrupole focusing incorporated into each drift tube, is about 5 times more efficient than the conventional Drift Tube Linac (DTL) structure. Details of the linac structures and their calculated performance will be presented.  
 
TUP09 The Heidelberg High Current Injector: A Versatile Injector for Storage Ring Experiments rfq, ion-source, storage-ring, extraction 309
 
  • R. von Hahn, M. Grieser, R. Repnow, D. Schwalm, C.P. Welsch
    MPI-K, Heidelberg
  The High Current Injector (HCI) was designed and built as a dedicated injector for the Test Storage Ring in Heidelberg to deliver mainly singly charged Li- and Be-ions. After start for routine operation in 1999 the HCI delivered stable beams during the following years for about 50 % of the experiments with very high reliability. Due to the requirements from the experiment the HCI changed during that period from a machine for singly charged positive ions to an injector for a large variety of molecules as well as positively or negatively charged light ions. After successful commissioning of the custom built 18 GHz high power ECR-source at its present test location various modifications and additions were made in preparation of a possible conversion into an injector for highly charged heavy ions as a second phase. This paper gives an overview of the experience gained in the passed 5 years and presents the status of the upgrade of the HCI.  
 
TUP10 Design of a Deuteron RFQ for Neutron Generation rfq, ion-source, proton, target 312
 
  • Z.Y. Guo, J. Chen, J. Fang, Y.R. Lu, S.X. Peng, Z.Z. Song, J.X. Yu, C. Zhang, K. Zhu
    PKU/IHIP, Beijing
  • A. Schempp
    IAP, Frankfurt-am-Main
  A deuteron RFQ is designed for neutron generation with 9Be(d,n)10B reaction. Considering the limitation of available RF transmitter, the frequency was chosen as 201.5 MHz and the peak RF power was set to 400 kW with 10% duty factor. The deuteron beam will be extracted from an ECR ion source also with 10% duty factor and then be accelerated to about 2 MeV by RFQ with high transmission efficiency. The system will be described and the design results of particle dynamics and structure will be given.  
 
TUP11 High current RFQ using laser ion source rfq, laser, plasma, ion-source 315
 
  • M. Okamura, R.A. Jameson, J. Takano, K. Yamamoto
    RIKEN, Saitama
  • R. Becker, A. Schempp
    IAP, Frankfurt-am-Main
  • T. Fujimoto
    AEC, Chiba
  • T. Hattori, N. Hayashizaki
    TIT, Tokyo
  • Y. Iwata, S. Shibuya
    NIRS, Chiba-shi
  • H. Kashiwagi
    JAERI/ARTC, Gunma-ken
  A new RFQ was fabricated for very high current heavy ions. The designed target current is 100 mA with cabon 4+ beam. Acceleration test result will be reported at the conference.  
 
TUP13 Test and First Experiments with the new REX-ISOLDE 200 MHz IH-Structure injection, impedance, linac, acceleration 318
 
  • T. Sieber
    CERN, Geneva
  • D. Habs, O.K. Kester
    LMU, Garching
  For the REX-ISOLDE accelerator, a new accelerating structure is at the moment installed and tested. It willl raise the final energy from the present 2.3 MeV/u to 3 MeV/u. The aim is to increase the mass range of the nuclei available for nuclear spectroscopy from mass 40 to mass 80. The new accelerator component is a 0.5 m IH-structure, working at the double REX frequency of 202.56 MHz. It was originally developed as a 7-Gap resonator for the MAFF* project and later adapted to the requirements at REX by changing from a 7-Gap to a 9-Gap resonator to match the lower injection energy. The poster presents the design of the resonator and the results of the rf-tests, commissioning and first operation during the 2004 running period.

*H. Bongers et al., The IH-7-Gap Resonators of the Munich Accelerator for Fission Fragments (MAFF) Linac, proceedings of the PAC2001, Chicago, June 2001, p.3945

 
 
TUP14 Status of the RFI Linac Prototype linac, rfq, ion-source, quadrupole 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.  
 
TUP15 Space Charge Compensation in Low Energy Proton Beams electron, emittance, space-charge, proton 324
 
  • A.B. Ismail, U.D. Uriot
    CEA/DSM/DAPNIA, Gif-sur-Yvette
  • R. Duperrier
    CEA/DAPNIA-SACM, Gif-sur-Yvette Cedex
  • N. Pichoff
    CEA/DAM, Bruyères-le-Châtel
  High power accelerators are being studied for several projects including accelerator driven neutron or neutrino sources. The low energy part of these facilities has to be carefully optimized to match the beam requirements of the higher energy parts. In this low energy part, the space charge self force, induced by a high intensity beam, has to be carefully managed. This nonlinear force can generate a high irreversible emittance growth of the beam. To reduce space charge effects, neutralization of the beam charge can be done by capturing some particles of the ionised residual gas in the vacuum chamber. This space charge compensation (SCC) regime complicates the dynamic study. Modelling the beam behaviour in such regime would be a significant contribution to the development of high intensity accelerators. Numerical and experimental study of SCC is in progress on the Saclay High Intensity Proton Injector. Experimental measurements and 2D/3D simulations of proton beam SCC will be presented.  
 
TUP26 Alternating Phase Focusing in Low-Velocity Heavy-Ion Superconducting Linac focusing, linac, emittance, heavy-ion 348
 
  • P.N. Ostroumov, K.W. Shepard
    ANL/Phys, Argonne, Illinois
  • A. Kolomiets
    ITEP, Moscow
  • E.S. Masunov
    MEPhI, Moscow
  The low-charge-state injector linac of the RIA post-accelerator is based on ~60 independently phased SC resonators providing total ~70 MV accelerating potential. The low charge-state beams, however, require stronger transverse focusing, particularly at low velocities, than is used in existing SC ion linacs. For the charge-to-mass ratios considered here (q/A = 1/66) the proper focusing can be reached by the help of strong SC solenoid lenses with the field up to 15 T. Magnetic field of the solenoids can be reduced to 9 T applying an Alternating Phase Focusing (APF). A method to set the rf field phases has been developed and studied both analytically and by the help of the three-dimensional ray tracing code. The paper discusses the results of these studies.  
 
TUP27 Acceleration of Several Charge States of Lead Ion in CERN LINAC3 rfq, linac, acceleration, injection 351
 
  • V. Coco, J.A. Chamings, A.M. Lombardi, E.Zh. Sargsyan, R. Scrivens
    CERN, Geneva
  CERN’s LINAC3 is designed to accelerate a 100 μAe Pb25+ ion beam from 2.5 keV/u to 4.2 MeV/u. The beam is then stripped using a carbon foil and the resulting 25 μAe 54+ beam is accumulated and cooled in the Low Energy Ion Ring (LEIR) before transfer to the Proton Synchrotron (PS) and ultimately to the Large Hadron Collider (LHC). The Pb25+ ions are selected with a spectrometer from a mixture of ten charge states produced by an Electron Cyclotron Resonance (ECR) source. In view of the fact that the stripping efficiency to Pb54+ is mostly dependent on energy and not on initial charge state, the feasibility of simultaneously accelerating to 4.2 MeV/u several charge states has been investigated. In this paper we report two possible technical solutions, their advantage in terms of intensity for the downstream machines and the experimental results supporting these conclusions.  
 
TUP56 Simulation of RF Breakdown Effects on NLC Beam electron, simulation, linac, acceleration 396
 
  • V.A. Dolgashev
    SLAC/ARDB, Menlo Park, California
  • T.O. Raubenheimer
    SLAC/NLC, Menlo Park, California
  The linacs of the Next Linear Collider (NLC) will contain several thousand traveling wave X-Band accelerator structures operating at input power of about 60 MW. At this input power prototypes of NLC structures have breakdown rates lower than one breakdown in ten hours. RF breakdowns disrupt flow of energy inside the structure and create arcs with electron and ion currents. Electromagnetic fields of these currents interact with the NLC beam. We simulated deflection of the NLC beam caused by breakdown currents using the particle-in-cell code MAGIC. In this paper we present modeling considerations and simulation results.  
 
TUP82 Low Energy Beam Transport using Space Charge Lenses space-charge, rfq, emittance, focusing 465
 
  • O. Meusel, A. Bechtold, H. Klein, J. Pozimski, U. Ratzinger, A. Schempp
    IAP, Frankfurt-am-Main
  Gabor lenses provide strong cylinder symmetric electric focusing using a confined nonneutral plasma. The density distribution of the enclosed space charge is defined by the enclosure conditions in transverse and longitudinal direction. For a homogeneous charge density distribution the resulting electrostatic field and therefrom the focusing forces inside the space charge cloud are linear. Additionally in case of a positive ion beam the space charge of the confined electrons causes compensation of the ion beam space charge forces. To study the capabilities of a Gabor double lens system to match an ion beam into a RFQ a testinjector was installed at the IAP and put into operation successfully. First beam profiles and emittance measurements as well as measurements of the beam energy and energy spread have already been performed and show satisfactory results and no significant deviation from the theoretical predictions. To verify the beam focusing of bunched beams using this lens type at beam energies up to 500 keV a new high field Gabor lens was build and will be installed behind of the RFQ.  
 
WE201 Results from the Initial Operations of the SNS Front End and Drift Tube Linac emittance, linac, rfq, ion-source 533
 
  • V. Aleksandrov
    ORNL/SNS, Oak Ridge, Tennessee
  The Spallation Neutron Source accelerator systems will deliver a 1 GeV, 1.44 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of an H- injector (the Front-End), capable of producing one millisecond long pulses with 38 mA of peak current at a repetition rate of 60 Hz, a 1 GeV linear accelerator, an accumulator ring and associated transport lines. A 2.5 MeV beam from the injector is accelerated to 86 MeV in the Drift Tube Linac, then to 185 MeV in a Coupled-Cavity Linac and finally to 1 GeV in a Superconducting Linac. The staged beam commissioning of the accelerator is proceeding in parallel with component installation. The Front End and Drift Tube Linac tanks 1-3 have been commissioned at ORNL. The primary design goals of peak current, transverse emittance and beam energy have been achieved. Beam with 38 mA peak current, 1 msec beam pulse length, and 1 mA average beam current has been accelerated through the DTL tank 1. Results and status of the beam commissioning program will be presented.

* on behalf of the SNS Project

 
Transparencies
 
WE202 Recent Results in the Field of High Intensity CW Linac Development for RIB Production linac, target, rfq, proton 538
 
  • A. Pisent
    INFN/LNL, Legnaro, Padova
  High Intensity CW Linacs have been proposed as driver accelerators for RIB production in various projects, since thy can drive in steady conditions a MW power range target for the production of spallation neutrons that induce fission in a natural uranium target. Particularly important for this application, with a relatively low beam current, is the necessity to develop a superconducting intermediate energy part with good power conversion efficiency. The second specific requirement of RIB facility drivers, that is also fulfilled by a superconducting intermediate energy linac, is the necessity to keep some flexibility in the species that can be accelerated (deuterons or light ions). In EURISOL RTD project a 1 GeV 5 mA proton linac, has been proposed for this application. In SPES project, recently approved for its initial phase at LNL, a lower energy proton beam will be used on a solid target. The results of the specific R&D programs on in the field of CW RFQ and superconducting low energy linacs will be illustrated. In particular for LNL the status of the RFQ construction and the superconducting cavities prototype tests will be given.  
Transparencies
 
TH101 Status of the J-PARC Linac, Initial Results and Upgrade Plan linac, rfq, emittance, proton 554
 
  • Y. Yamazaki
    JAERI/LINAC, Ibaraki-ken
  The J-PARC linac building will be completed by March, 2005, when the installation of the linac components will start. On the other hand, the front end linac, comprising the 3 MeV RFQ linac, the MEBT with the beam chopper, and the 20 MeV DTL first tank, is under beam commissioning in the KEK site. A peak current of 30 mA, which is enough for the 0.6 MW operation of Rapid-Cycling Synchrotron (RCS), was accelerated up to 20 MeV on the second day of the beam commissioning, last November. The detailed study of the system is under way, including the stability test of many components. The front end linac will be shipped to the JAERI Tokai site after the building completion there. The beam commissioning of the 181 MeV linac will start in September 2006, that of the 3 GeV RCS in May, 2007, and that of the 50 GeV Main Synchrotron (MR) in November 2007. The beam acceleration in the MR will be done by March, 2008. It is strongly recommended by the government committee that the upgrade to the 400 MeV linac should start immediately after the completion of the above accelerator system, that is, in April 2008, with the period of three years, aiming the 1 MeV RCS beam power.  
Transparencies
 
TH102 Overview of High Intensity Linac Programs in Europe linac, proton, rfq, target 559
 
  • M. Vretenar, R. Garoby
    CERN, Geneva
  Recent years have seen a boost in the European Union (EU) engagement for accelerator research in Europe. Laboratories and institutions from member states are invited to combine their efforts and to define common goals and strategies, in order to receive a financial support up to 50% of the total project cost. In the field of High Intensity Linacs, the EU had already supported the EURISOL initiative for nuclear physics, which this year is applying for funding of a Design Study, and the development of linacs for Waste Transmutation. More recently, an initiative for high-energy physics has been approved, which includes a programme for the development of pulsed linac technologies. Together with the ongoing national projects, these European initiatives represent a strong focussed effort towards the development of linac technologies, intended to overcome difficulties coming from decreasing national budgets. This paper presents a summary of the requests coming from the European physics communities and an overview of linac R&D activities sponsored by the EU, together with some information on parallel national projects. The parameter choices as well as the main technical features of the different projects are presented and compared.  
Transparencies
 
TH103 Summary of the Argonne Workshop on High Gradient RF electron, linac, linear-collider, simulation 564
 
  • J. Norem
    ANL, Argonne, Illinois
  Workshop on High Gradient rf was held at Argonne from October 7 - 9, 2003. This workshop reviewed the problems encountered when a number of accelerator technologies approached the high gradient limits. The aim of the workshop was to involve materials scientists and try to look at trigger mechanisms and surface interactions, in addition to reviewing progress. Talks were presented on superconducting rf, progress with high and low frequency copper cavities, and dielectrics. The focus was on both experimental and theoretical aspects of the problem. The overall picture presented at the workshop will be summarized.  
Transparencies
 
TH204 End-to-End Beam Dynamics Simulations for the ANL-RIA Driver Linac linac, simulation, emittance, beam-losses 584
 
  • P.N. Ostroumov
    ANL/Phys, Argonne, Illinois
  The proposed Rare Isotope Accelerator (RIA) Facility consists of a superconducting (SC) 1.4 GV driver linac capable of producing 400 kW beams of any ion from hydrogen to uranium. The driver is configured as an array of ~350 SC cavities, each with independently controllable rf phase. For the end-to-end beam dynamics design and simulation we use a dedicated code, TRACK. The code integrates ion motion through the three-dimensional fields of all elements of the driver linac beginning from the exit of the electron cyclotron resonance (ECR) ion source to the production targets. TRACK has been parallelized and is able to track large number of particles in randomly seeded accelerators with misalignments and a comprehensive set of errors. The simulation starts with multi-component dc ion beams extracted from the ECR. Beam losses are obtained by tracking up to million particles in hundreds of randomly seeded accelerators. To control beam losses a set of collimators is applied in designated areas. The end-to-end simulations with the TRACK code have been extremely useful for studies of different options of the driver linac design with respect to beam quality, beam losses and sensitivity of beam parameters to various types of errors.  
Transparencies
 
TH301 Intermediate-Velocity Superconducting Accelerating Structures linac, proton, impedance, acceleration 589
 
  • J. R. Delayen
    Jefferson Lab, Newport News, Virginia
  In the last decade, one of the most active areas in the application of the superconducting (SC) rf technology has been for the acceleration of ions to medium energies (~1 GeV/amu). One such accelerator is under construction in the US while others are being proposed in the US, Japan, and Europe. These new facilities require SC accelerating structures operating in a velocity region that has until recently been unexplored, and new types of structures optimized for the velocity range from ~0.2 to ~0.8 c have been developed. We will review the properties of these intermediate-velocity structures, the status of their development, as well as present an overview of the medium-energy superconducting ion accelerator designs being developed world-wide.  
Transparencies
 
TH302 End-to-End Beam Simulations for the MSU RIA Driver Linac linac, emittance, simulation, alignment 594
 
  • X. Wu, M. Doleans, D. Gorelov, T.L. Grimm, F. Marti, R.C. York, Q. Zhao
    NSCL, East Lansing, Michigan
  The Rare Isotope Accelerator (RIA) driver linac proposed by Michigan State University (MSU) will use a 10th sub-harmonic based, superconducting, cw linac to accelerate light and heavy ions to final energies of ≤400 MeV/u with beam powers of 100 to 400 kW. The driver linac uses superconducting quarter-wave, half-wave, and six-cell elliptical cavities with frequencies ranging from 80.5 MHz to 805 MHz for acceleration, and superconducting solenoids and room temperature quadrupoles for transverse focusing. For the heavier ions, two stages of charge-stripping and multiple-charge-state acceleration will be used to meet the beam power requirements and to minimize the requisite accelerating voltage. End-to-end, three-dimensional (3D), beam dynamics simulations from the ECR to the radioactive beam production targets have been performed. These studies include a 3D analysis of multi-charge-state beam acceleration, evaluation of transverse misalignment and rf errors on the machine performance, modeling of the charge-stripping and stripping-chicane performance, and beam switchyard design. The results of these beam dynamics studies will be presented, and further planned beam dynamics studies will be discussed.  
Transparencies
 
THP03 DESIGN IMPROVEMENT OF THE RIA 80.5 MHZ RFQ rfq, emittance, linac, simulation 599
 
  • Q. Zhao, V. Andreev, M. Doleans, D. Gorelov, T.L. Grimm, W. Hartung, F. Marti, S.O. Schriber, X. Wu, R.C. York
    NSCL, East Lansing, Michigan
  An 80.5 MHz, continuous-wave, normal-conducting, radio-frequency quadrupole (RFQ) was designed for the front end of the Rare Isotope Accelerator (RIA) driver linac. It will accelerate various ion beams (hydrogen up to uranium) from 12 keV/u to about 300 keV/u. The 4-meter-long RFQ accepts the pre-bunched beam from the low energy beam transport (LEBT) and captures more than 80% with a current of ~0.3 mA. Beam dynamics simulations show that the longitudinal output emittance is small for both single- and two-charge-state ion beams with an external multi-harmonic buncher. A 4-vane resonator with magnetic coupling windows was employed in the cavity design to provide large mode separation, high shunt impedance, and a small transverse dimension. The results of beam dynamics as well as the electromagnetic simulations are presented.  
 
THP05 Superconducting beta=0.15 Quarter-Wave Cavity for RIA linac, vacuum, superconductivity, resonance 605
 
  • M. Kelly
    ANL, Argonne, Illinois
  • Z.A. Conway, J.D. Fuerst, M. Kedzie, K.W. Shepard
    ANL/Phys, Argonne, Illinois
  A production-design 115 MHz niobium quarter-wave cavity with a full stainless steel helium jacket has been built and tested as part of the R&D for the Rare Isotope Accelerator (RIA) driver linac. The two-gap cavity is designed to accelerate ions over the velocity range 0.14<β<0.24. Processing of the cavity RF surfaces, including high-pressure rinsing and assembly of the cavity with a moveable high-power RF coupler were all performed under clean room conditions. Cold test results including high-field cw operation, microphonics, and helium pressure sensitivity will be presented in this paper. Performance of a pneumatically actuated slow-tuner device suitable not only for this cavity but a number of other cavities required for RIA will also be discussed.  
 
THP08 The Frankfurt Funneling Experiment rfq, linac, emittance, simulation 614
 
  • A. Schempp, U. Bartz, N. Müller, J. Thibus, H. Zimmermann
    IAP, Frankfurt-am-Main
  Funneling is a procedure to multiply beam currents of rf-accelerators at low energies. In the ideal case the beam current can be multiplied in several stages without emittance growth. The Frankfurt Funneling Experiment consists of two ion sources, a Two-Beam RFQ accelerator, two different funneling deflectors and a beam diagnostic equipment system. The whole set-up is scaled for He+ instead of Bi+ for the first funneling stage of a HIIF driver. The progress of our experiment and the results of the simulations will be presented.  
 
THP10 Tuner Design for High Power 4-Rod-RFQs rfq, linac, simulation, vacuum 617
 
  • A. Schempp, L. Brendel, B. Hofmann, H. Liebermann
    IAP, Frankfurt-am-Main
  The performance of high power RFQ linacs, as used in spallations sources and proposed for projects like ADxy, IFMIF or high duty factor drivers for RIB application are limited by beam dynamics properties as well as technical limits like sparking, power density, cooling and thermal stresses. A "one piece structure" even possible in theory has to have means for tuning the real fields like exchangable or moving tuners. Tuner design features will be discussed and results will be presented.  
 
THP13 Construction of a 161 MHz, β=0.16 Superconducting Quarter Wave Resonator with Steering Correction for RIA light-ion, linac, vacuum, emittance 626
 
  • A. Facco
    INFN/LNL, Legnaro, Padova
  • C. Compton, T.L. Grimm, W. Hartung, F. Marti, R.C. York
    NSCL, East Lansing, Michigan
  • V. Zvyagintsev
    TRIUMF, Vancouver
  We have built a 161 MHz, β=0.16 superconducting Quarter Wave Resonator with steering correction for the low beta section of RIA. This bulk niobium, double wall cavity, compatible with both separate vacuum between beam line and cryostats or unified one, was designed in collaboration between MSU-NSCL and LNL. The design is suitable for extension to other frequencies, e.g. to obtain the 80 MHz, β=0.085 cavity required in RIA. The shaped drift tube allows correction of the residual QWR steering that can cause emittance growth especially in light ions; this could make this resonator a good alternative to Half-Wave resonators in high intensity proton-deuteron linacs, like the SPES injector project at LNL. First test results will be presented.  
 
THP14 High Beta Cavity Optimization for ISAC-II linac, quadrupole, 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.  
 
THP18 The Acceleration Test of the APF-IH-LINAC linac, acceleration, focusing, proton 636
 
  • K. Yamamoto, M. Okamura
    RIKEN, Saitama
  • T. Hattori
    TIT, Tokyo
  • S. Yamada
    NIRS, Chiba-shi
  We manufactured an IH linac with Alternating Phase Focusing as a test machine for medical accelerator injection. It will accelerate C4+ ions from 40 keV/u up to 2 MeV/u. The tank length is around 1.5 m, operation frequency is 100 MHz. We have succeeded to accelerate protons with a simple acceleration system, consisting of a PIG ion source, bending magnets and focus lenses, less than 5m long. This IH linac was calculated using a simple thin lens approximation. Now we are making a beam-tracking program using the results of the electro-magnetic simulation soft (Micro-Wave-Studio, OPERA-3D); it has the merit of easily calculating the 3D-beam dynamics including non-linear effects. We will report the test, the beam simulations and comparisons of the test to the simulations.  
 
THP22 3D Beam Dynamics Simulation in Undulator Linac simulation, undulator, linac, bunching 642
 
  • E.S. Masunov, S.M. Polozov
    MEPhI, Moscow
  The ion beam can be bunched and accelerated in linear accelerator with RF undulator (UNDULAC-RF). The acceleration and focusing of beam can be realized without using a synchronous wave*. In this paper the computer simulation of high intensity ion beam dynamics in UNDULAC-RF was carried out by means of the "superparticles" method. The computer simulation and optimization of ion dynamics consist of two steps. At the first, the equations of particles motion in polyharmonic fields are devised by means of smooth approximation. Hamiltonian analysis of these equations allows to find a velocity of reference particle in polyharmonic field and to formulate the conditions of good longitudinal bunching and transverse focusing beam. At the second, the 3D ion beam dynamics simulation in an UNDULAC is governed by founded functions of reference particle velocity and a ratio of amplitude harmonics. The influence of the space charge on RF focusing conditions, transmission coefficient, longitudinal and transverse emittances, and other acceleration system characteristics are investigated by computer simulation.

*Masunov E.S., Sov. Phys.-Tech. Phys., vol. 35, No. 8, p. 962, 1990.

 
 
THP23 An Electrode With Molybdenum-Cathode and Titanium-Anode to Minimize Field Emission Dark Currents cathode, electron, vacuum, feedback 645
 
  • T. Nakanishi, F. Furuta, T. Gotou, M. Kuwahara, K. Naniwa, S. Okumi, M. Yamamoto, N. Yamamoto, K. Yasui
    DOP Nagoya, Nagoya
  • H. Matsumoto, M. Yoshioka
    KEK, Ibaraki
  • K. Togawa
    RIKEN Spring-8 Harima, Hyogo
  A systematic study to minimize field emission dark currents from high voltage DC electrode has been continued. It is clearly demonstrated that much lower field emissions observed for Molybdenum (Mo) and Titanium (Ti) in comparison to Stainless-steel and Copper. Furthermore, by analyzing gap-length dependence data of the dark current from Mo and Ti, we can find a method to separate the primary field emission currents (FEC) from secondary induced currents (SIC). The latter currents will be created by possible bombardments of metal surface of anode or cathode by electrons or positive ions, respectively. From this data analysis, it is suggested that Mo is suitable for cathode due to its smallest FEC, and Ti is adequate for anode due to relatively small SIC. This prediction was confirmed by our experiment using a pair of Mo and Ti electrode, which showed the total dark current is suppressed below 1 nA at 105 MV/m applied for an area of 7 mm2 with a gap-length of 1.0 mm. Therefore this Mo-Ti electrode seems useful for a high field gradient DC gun, especially for a GaAs-photocathode gun using an NEA (Negative Electron Affinity) surface.  
 
THP50 The CEBAF RF Separator System Upgrade power-supply, resonance, controls, cathode 721
 
  • C. Hovater, M. Augustine, A. Guerra, R. Nelson, R.A. Terrel, M. Wissmann
    TJNAF, Newport News, Virginia
  The CEBAF accelerator uses RF deflecting cavities operating at the third sub-harmonic (499 MHz) of the accelerating frequency (1497 MHz) to “kick” the electron beam to the experimental halls. The cavities operate in a TEM dipole mode incorporating mode enhancing rods to increase the cavity’s transverse shunt impedance. As the accelerators energy has increased from 4 GeV to 6 GeV the RF system, specifically the 1 kW solid state amplifiers, have become problematic, operating in saturation because of the increased beam energy demands. Two years ago we began a study to look into replacement for the RF amplifiers and decided to use a commercial broadcast Inductive Output Tube (IOT) capable of 30 kW. The new RF system uses one IOT amplifier on multiple cavities as opposed to one amplifier per cavity originally. In addition the new RF system supports the proposed 12 GeV energy upgrade to CEBAF. Currently we are halfway through the upgrade with two IOTs in operation and two more to be installed. This paper reports on the new RF system and the IOT performance.  
 
THP74 Laser Produced Ions as an Injection Beam for Cancer Therapy Facility laser, target, proton, plasma 782
 
  • A. Noda, M. Hashida, Y. Iwashita, S. Nakamura, S. Sakabe, S. Shimizu, T. Shirai, H. Tongu
    Kyoto ICR, Kyoto
  • H. Daido
    JAERI APRC, Ibaraki-ken
  • A. Fukumi, Z. Li, K. Matsukado
    NIRS, Chiba-shi
  • T. Hosokai, H. Iijima, K. Kinoshita, M. Uesaka, T. Watanabe, K. Yoshii
    UTNL, Ibaraki
  • T. Takeuchi
    DOP Nagoya, Nagoya
  Ion production from a solid target by a high-power short pulse laser has been investigated to replace the injector linac of the synchrotron dedicated for cancer therapy. As the high power laser, the laser with the peak power of 100 TW and minimum pulse duration of 20 fs which has been developed at JAERI Kansai Research Establishment, is assumed. Laser produced ions with 100% energy spread is energy selected within ±5% and then phase rotated with use of the RF electric field synchronized to the pulse laser, which further reduces the energy spread to ±1%. The scheme of the phase rotation is presented together with the experimental results of laser production from the thin foil target.  
 
THP86 Low Power Measurements on a Finger Drift Tube Linac linac, simulation, booster, rfq 800
 
  • A. Schempp, K.-U. Kühnel
    IAP, Frankfurt-am-Main
  • C.P. Welsch
    MPI-K, Heidelberg
  The efficiency of RFQs decreases at higher particle energies. The DTL structures used in this energy regions have a defocusing influence on the beam. To achieve a focusing effect, fingers with quadrupole symmetry were added to the drift tubes. Driven by the same power supply as the drift tubes, the fingers do not need an additional power source or feedthrough. Beam dynamics have been studied with PARMTEQ . Detailed analysis of the field distribution was done and the geometry of the finger array has been optimized with respect to beam dynamics. A spiral loaded cavity with finger drift tubes was built up and low power measurements were done. In this contribution, the results of the rf simulating with Microwave Studio are shown in comparison with bead pertubation measurement on a prototype cavity.  
 
FR203 The Science of Radioactive Ion Beams 857
 
  • B. Sherrill
    NSCL, East Lansing, Michigan
  The primary intellectual challenge of nuclear physics is to understand the nature of strongly interacting matter and how the features of nuclear many-body systems derive from the fundamental forces and properties of their constituent parts. In nuclear science, interestingly, atomic nuclei present one of the most difficult problems to address. However, a comprehensive understanding of nuclear properties is essential to our ability to model the chemical evolution of the Universe, use nuclei for tests of the fundamental symmetries of nature and assess any number of nuclear technologies. Until recently, the fact that experiments had to be carried out with the limited range of stable isotopes found in nature has severely constrained our understanding. However, the current and next generation of radioactive ion beam facilities will remove this constraint. This talk will endeavor to summarize the most important opportunities made available with the next generation of radioactive ion beam facilities.  
Transparencies
 
FR204 The Physics Perspectives at the Future Accelerator Facility FAIR antiproton, target, synchrotron, hadron 858
 
  • J. Stroth
    GSI, Darmstadt
  The physics perspective of the approved future international accelerator Facility for Anti-proton and Ion Research (FAIR) near Darmstadt, Germany will be outlined. The physics programme will comprise many body aspects of matter ranging from macroscopic system like highly correlated plasmas down to the properties of baryons and nuclear matter at high baryon densities. Through fragmentation of intense ion beams investigations with beams of short-lived radioactive nuclei far from stability will be possible. The addressed physics questions concern nuclear structure at the drip-lines, areas of astrophysics and nucleo-synthesis in supernovae and other stellar processes, as well as tests of fundamental symmetry. The structure of baryons and their limits of their existence is the interest of the two large experimental set-ups PANDA and CBM. Finally QED will be studied in extremely strong field effects and also the interaction of ions with matter. The future facility will feature a double-ring synchrotron SIS100/300 and a system of associated storage rings for beam collection, cooling, phase space optimisation and experimentation.  
Transparencies