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heavy-ion

 
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MOZAPA01 Approaches to High Intensities for FAIR ion, rfq, ion-source, UNILAC 24
 
  • P.J. Spiller, W. Barth, L.A. Dahl, H. Eickhoff, R. Hollinger, P.S. Spaedtke
    GSI, Darmstadt
  A new accelerator complex is planned to generate highest intensities of heavy ion and proton beams for the Facility for Antiproton and Ion Research (FAIR) at GSI. The two new synchrotrons, SIS100 and SIS300 which deliver the primary beams to the FAIR target stations, will make use of the existing GSI accelerators UNILAC and SIS18 as injectors. In order to reach the desired intensities close to 1012 uranium ions and 2.5 x 1013 protons per pulse, a substantial upgrade program of the existing facility is being prepared. The well defined technical subprojects of these upgrade programs and the concepts for approaching the intensity goals of SIS100/300 will be described.  
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MOPCH133 An Analytic Calculation of the Electron Cloud Linear Map Coefficient electron, simulation, LHC, RHIC 357
 
  • U. Iriso
    CELLS, Bellaterra (Cerdanyola del Vallès)
  • S. Peggs
    BNL, Upton, Long Island, New York
  The evolution of the electron density during multibunch electron cloud formation can often be reproduced using a bunch-to-bunch iterative map formalism. The coefficients that parameterize the map function are readily obtained by fitting to results from compute-intensive electron cloud simulations. This paper derives an analytic expression for the linear map coefficient that governs weak cloud behaviour from first principles. Good agreement is found when analytical results are compared with linear coefficient values obtained from numerical simulations. This analysis is useful in predicting thresholds beyond which electron cloud formation occurs, and thus in determining safety regions in parameter space where an accelerator can be operated without creating electron clouds. The formalism explicitly shows that the multipacting resonance condition is not a sine qua non for electron cloud formation.  
 
MOPCH139 Results and Experience with Single Cavity Tests of Medium Beta Superconducting Quarter Wave Resonators at TRIUMF linac, acceleration, ion, radiation 375
 
  • V. Zviagintsev, K. Fong, M.P. Laverty, R.E. Laxdal, A.K. Mitra, T.C. Ries, I. Sekachev
    TRIUMF, Vancouver
  A heavy ion superconducting linac is being installed at ISAC/TRIUMF. A first stage of the ISAC-II upgrade will see the installation of 20 quarter wave bulk niobium cavities (Beta0=0.057,0.071). The cavities operate CW at 106MHz with design peak fields of Ep=30MV/m, Bp=60mT while delivering an accelerating voltage of 1.08MV at <7W power consumption. All cavities have been tested in a single cavity test stand with twenty of twenty-one meeting ISAC-II specifications. The cavity test results will be presented. In particular we will discuss our experience with BCP vs. EP surface treatments and with Q-disease. In addition the tuning plates of two of the cavities were modified to provide a unique compensation to the resonant frequency.  
 
MOPLS022 On the Feasibility of Polarized Heavy Ions in RHIC ion, RHIC, resonance, proton 586
 
  • W.W. MacKay
    BNL, Upton, Long Island, New York
  Heavy nonspherical ions such as uranium have been proposed for collisions in RHIC. When two such ions collide with their long axes aligned, then the plasma density might be as much as 60% higher. Since the collisions might have any orientation of the two nuclei, the alignment of the nuclei must be inferred from a complicated unfolding of multiplicity distributions. Instead, if it is possible to polarize the ions and control the orientation in RHIC, then a much better sensitivity could be obtained. This paper investigates the manipulation of such polarized ions with highly distorted shapes in RHIC. Several ion species are considered as possibilities with either full or partial Siberian snakes in RHIC.  
 
TUPCH010 Profile Measurement by Beam Induced Fluorescence for 60 MeV/u to 750 MeV/u Heavy Ion Beams ion, background, vacuum, photon 1013
 
  • P. Forck, C. Andre, F. Becker, H. Iwase
    GSI, Darmstadt
  • D. Hoffmann
    TU Darmstadt, Darmstadt
  At the planned heavy ion facility FAIR very intense beams of heavy ions will be transported between various synchrotrons and focused on targets for secondary ion productions. For the transverse profile determination only non-destructive methods are suited due to the large deposed beam power. We investigated experimentally the Beam Induced Fluorescence (BIF) method. Due to the atomic collision by the beam ions the residual gas N2 is excited to fluorescence levels. Single photon detection is performed by a double MCP image intensifier coupled to a digital CCD camera. Extensive experimental studies (with the today available lower ion currents) were performed to determine the photon yield and the background contribution for different ion species and beam energies. The measured profiles show a good correspondence to other methods as long as the vacuum pressure by a regulated N2 inlet is below 10-1 mbar. Based on the experimental results, the layout for a BIF profile determination will be discussed.  
 
TUPCH124 Improvement of Co-based Amorphous Core for Untuned Broadband RF Cavity impedance, acceleration, LEFT, synchrotron 1304
 
  • A. Sugiura, M. Kanazawa, T. Misu, S. Yamada
    NIRS, Chiba-shi
  • K. Katsuki, T. Kusaka, K. Sato
    Toshiba, Yokohama
  We have developed a cobalt-based amorphous core as a new magnetic-alloy (MA) core for the loaded RF cavity. Because of its permeability found to be approximately twice as high as that of FINEMET, this MA core is an excellent candidate for constructing a compact broadband RF cavity with less power consumption. In this report, we present our recent studies of the Co-based amorphous core's physical properties and performance. Improvement of the new core coated by new materials surface of ribbon is also described.  
 
TUPCH149 Design of a 10 MHz Heavy Ion RFQ for a RIA Post Accelerator rfq, ion, target, superconductivity 1370
 
  • S.O. Schriber, V. Andreev
    NSCL, East Lansing, Michigan
  Design of a 10 MHz heavy ion RFQ for the RIA post accelerator is described. Main rf and mechanical parameters of the proposed accelerator are given. This 10 MHz RFQ is capable of accelerating beams from an initial energy of 2 keV/u to 8 keV/u covering a charge to mass ratio from 1/10 to 1/240.  
 
TUPLS031 Commissioning of the ISAC-II Heavy Ion Superconducting Linac at TRIUMF linac, acceleration, ion, vacuum 1556
 
  • R.E. Laxdal, W. Andersson, K. Fong, M. Marchetto, A.K. Mitra, W.R. Rawnsley, I. Sekachev, G. Stanford, V.A. Verzilov, V. Zviagintsev
    TRIUMF, Vancouver
  A new heavy ion superconducting linac at TRIUMF is being installed to boost the final energy of radioactive beams from ISAC from 1.5MeV/u to above the Coulomb barrier. A first stage of 20MV consisting of five medium beta cryomodules each with four quarter wave bulk niobium cavities and a superconducting solenoid is being commissioned in early 2006. The cavities (Beta0=0.057, 0.071) operate cw at 106MHz with design peak fields of Ep=30MV/m, Bp=60mT while delivering an accelerating voltage of 1.08MV at ~4W power consumption. The report will summarize the commissioning results and early operating experience.  
 
TUPLS032 Superconducting Driver Linac for the New Spiral 2 Radioactive Ion Beam Facility GANIL ion, rfq, linac, ion-source 1559
 
  • T. Junquera
    IPN, Orsay
  The new Spiral 2 facility will deliver high intensity rare isotope beams for fundamental research in nuclear physics, and high neutron flux for multidisciplinary applications. Based into the ISOL and in-flight isotope production methods this facility will cover broad areas of the nuclide chart. The driver accelerator must deliver CW beams of deuterons (40 MeV, 5 mA) and heavy ions (q/A=1/3, 15 MeV/A, 1 mA). The injector is composed of two ion sources (deuterons and heavy ions) and a common RFQ cavity (88 MHz). The Superconducting Linac is composed of two sections of Quarter Wave Resonators (beta 0.07 and 0.12, frequency 88 MHz) with room temperature focusing devices. After two years of preliminary study, and following the recent decision to launch the construction phase, a complete design of the Driver Accelerator is presently completed. Important results have been obtained during the initial R&D phase, in particular on ion sources, RFQ and superconducting resonators prototypes. Status report on both the design and the prototype performances will be given in this contribution.  
 
TUPLS058 New Prestripping Section of the MILAC Linear Accelerator Designed for Accelerating a High Current Beam of Light Ions ion, focusing, acceleration, controls 1627
 
  • A.P. Kobets, V.A. Bomko, O.F. Dyachenko, Ye.V. Ivakhno, M.S. Lesnykh, Z.O. Ptukhina, V.N. Reshetnikov, S.S. Tishkin, V.P. Yashin, A.V. Zabotin, B.V. Zajtsev, V.G. Zhuravlev
    NSC/KIPT, Kharkov
  In the Kharkov Institute of Physics and Technology, the works on construction of a new prestripping section of the multicharge ion linear accelerator (MILAC) is performed. The task is set to provide acceleration of high current beams of light ions for research works on radiation material engineering and applied investigations. The new prestripping section is designed for accelerating ions with A/q=4 up to the energy of 1 MeV/u; after stripping they will be accelerated in the main section up to the energy of 8.5 MeV/u. Special operational mode will allow to increase noticeably the repetition rate with the same power consumption. The calculation results on beam dynamics in the structure with alternating phase focusing in the version with the stepped change of the synchronous phase, and calculations of electrodynamic characteristics of the accelerating structure of the interdigital type. The peculiarities of the construction of the accelerating structure are described.  
 
TUPLS081 Flat Beams and Application to the Mass Separation of Radioactive Beams emittance, ion, dipole, quadrupole 1687
 
  • P. Bertrand
    GANIL, Caen
  • J.-L. Biarrotte
    IPN, Orsay
  • D. Uriot
    CEA, Gif-sur-Yvette
  The notion of flat beam is now well established and has been proven theoretically and experimentally with applications for linear colliders. In this paper, we propose a new and simple demonstration of the "flat beam theorem", and a possible application in the frame of radioactive ion beams (RIB) production. It consists in using a magnetized multi-specie heavy ion beam extracted from a high frequency ECR source, decoupling the transverse phase planes in such a way to obtain a very small emittance in the horizontal one, and using a dipole to separate the isotopes. A design of such a transport and separation line will be proposed and commented.  
 
TUPLS126 Interaction of the CERN Large Hadron Collider (LHC) Beam with Carbon Collimators LHC, target, proton, simulation 1798
 
  • N.A. Tahir, D. Hoffmann
    GSI, Darmstadt
  • Y. Kadi, R. Schmidt
    CERN, Geneva
  • R. Piriz
    Universidad de Castilla-La Mancha, Ciudad Real
  • A. Shutov
    IPCP, Chernogolovka, Moscow region
  The LHC will operate at 7 TeV with a luminosity of 1034 cm-2s-1. Each beam will have 2808 bunches, with nominal intensity per bunch of 1.1x1011 protons. The energy stored in each beam of 362 MJ. In a previous paper the mechanisms causing equipment damage in case of a failure of the machine protection system was discussed, assuming that the entire beam is deflected into a copper target. Another failure scenario is the deflection of beam into carbon material. Carbon collimators and beam absorbers are installed in many locations around the LHC to diffuse or absorb beam losses. Since their jaws are close to the beam, it is very likely that they are hit first when the beam is accidentally deflected. Here we present the results of two-dimensional hydrodynamic simulations of the heating of a solid carbon cylinder irradiated by the LHC beam with nominal parameters, carried out using the BIG-2 computer code* while the energy loss of the 7 TeV protons in carbon is calculated using the well known FLUKA code**. Our calculations suggest that the LHC beam may penetrate up to 10 m in solid carbon, resulting in a substantial damage of collimators and beam absorbers.

*V. E. Fortov et al. Nucl. Sci. Eng. 123 (1996) 169. **A. Fasso et al. The physics models of FLUKA: status and recent development, CHEP 2003, La Jolla, California, 2003.

 
 
WEPCH086 Adiabatic Theory of Slow Extraction of Particles from a Synchrotron resonance, synchrotron, extraction, betatron 2119
 
  • S.A. Nikitin
    BINP SB RAS, Novosibirsk
  An analytical approach is developed to describe the process of slow extraction of particles from a synchrotron based on adiabatic crossing of the betatron resonance of the third order. An exact expression for the phase integral is found to analyze the conditions of oscillation amplitude growth near the resonance band. It allows one to directly define the interval of adiabatic motion from the start of decreasing the resonant tune to the beginning of fast increase of the oscillation amplitude. The interval distribution function is constructed for the cases of zero momentum spread and zero machine chromaticity as well as for the general case, taking into account non-zero momentum spread, non-zero chromaticity and synchrotron oscillations. Some numeric calculations of the time dependence of the extracted particle current are presented. It is shown that the momentum spread in the extracted beam can be minimized with the use of additional RF acceleration of particles during the slow extraction procedure.  
 
WEPCH168 Development toward Turn-key Beam Delivery for Therapeutic Operation at HIMAC extraction, ion, quadrupole, emittance 2325
 
  • T. Furukawa, T. Kanai, K. Noda, S. Sato, E. Takada, M. Torikoshi, S. Yamada
    NIRS, Chiba-shi
  • M. Katsumata, T. Shimojyu, T. Shiraishi
    AEC, Chiba
  Since 1994, more than 2500 cancer patients have been treated by carbon ion beam at HIMAC. To increase the number of patients per day, we have studied the reproducibility of the beam quality, such as the position, profile and intensity, during the operation. For this purpose, the accelerator needs high reproducibility to minimize the beam tuning time with more flexible scheme. Further, the irradiation system and the accelerator need to ensure dose uniformity. As a result of this study, it was found that a slight change of the magnetic field in the transport line would not affect the beam quality. However, a slight change of the horizontal tune strongly affects the beam quality because of a resonant slow-extraction. In this paper, we report about our investigation and present result of the development.  
 
WEPCH170 Development of Intensity Control System with RF-knockout Extraction at the HIMAC Synchrotron controls, extraction, synchrotron, ion 2331
 
  • S. Sato, T. Furukawa, K. Noda
    NIRS, Chiba-shi
  We have developed a dynamic intensity control system toward scanning irradiation at the HIMAC Synchrotron. In this system, for controlling the spill structure and intensities of the beams extracted from the synchrotron, the amplitude of the RF-knockout is controlled with the response of 10 kHz. Its amplitude modulation (AM) function is generated based on an analytical one-dimensional model of the RF-knockout slow-extraction. In this paper, we describe the system for controlling amplitude modulation including feedback and the experimental result.  
 
WEPCH184 Mechanical Properties of WC-Co by Nitrogen Ion Implantation: Improvement of Industrial Tools ion, ion-source, cathode, vacuum 2364
 
  • Y. Noh, B.Y. Kim, K. R. Kim, J.S. Lee
    KAERI, Daejon
  Ion implantation of WC-Co has been widely investigated for the improvement of wear resistance, but rarely for friction behavior. Although friction is closely associated with wear, more factors influence friction than wear, and low wear does not generally lead to low friction w6x. Therefore, we focus our study on the effects of ion implantation on the mechanical properties in WC-Co cermets, with particular interest in tool industry applications.