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heavy-ion

        
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MOPLT010 Collimation of Heavy Ion Beams in LHC ion, collimation, proton, scattering 551
 
  • H.-H. Braun, R.W. Assmann, A. Ferrari, J.-B. Jeanneret, J.M. Jowett
    CERN, Geneva
  • I.A. Pshenichnov
    RAS/INR, Moscow
  The LHC collimation system is designed to cope with requirements of proton beams having 100 times higher beam power than the nominal LHC heavy ion beam. In spite of this, specific problems occur for ion collimation, due to different particle-collimator interaction mechanism for ions and protons. Ions are subject to hadronic fragmentation and electromagnetic dissociation, resulting in a non-negligible flux of secondary particles of small angle divergence and Z/A ratios slightly different from the primary beam. These particles are difficult to intercept by the collimation system and can produce significant heat-load in the superconducting magnets when they hit the magnet vacuum chamber. A computer program has been developed to obtain quantitative estimates of the magnitude and location of the particle losses. Hadronic fragmentation and electromagnetic dissociation of ions in the collimators were considered within the frameworks of abrasion-ablation and RELDIS models, respectively. Trajectories of the secondary particles in the ring magnet lattice and the distribution of intercept points of these trajectories with the vacuum chamber are computed. Results are given for the present collimation system design and potential improvements are discussed.  
 
MOPLT029 All Digital IQ Servo-system for CERN Linacs linac, diagnostics, ion, controls 605
 
  • A. Rohlev, J. Broere, R. Garoby, I. Kozsar, J. Serrano
    CERN, Geneva
  A VME based control system has been developed and built at CERN for the servo loops regulating the field in linac accelerating structures. It is an all-digital system built on a single VME card, providing digital detection, processing, and modulation. It is foreseen to be used, in different versions, for the needs of both present and future CERN hadron linacs. The first application will be in the energy ramping RF chain of the CERN Heavy Ion Linac (linac 3). In addition to regulating the cavity field, the system incorporates the measurement and control of the cavity resonance as well as an imbedded loop stabilizing the gain and the phase of the final amplifier operating near saturation. The design principle and the experimental results are described.  
 
MOPLT042 Interaction of the CERN Large Hadron Collider (LHC) Beam with Solid Metallic Targets target, proton, simulation, collider 641
 
  • N.A. Tahir, D.H. Hoffmann
    GSI, Darmstadt
  • V. Fortov, I. Lomonosov, A. Shutov
    IPCP, Chernogolovka, Moscow region
  • B. Goddard, V. Kain, R. Schmidt
    CERN, Geneva
  • R. Piriz, M. Temporal
    Universidad de Castilla-La Mancha, Ciudad Real
  The LHC will operate at 7 TeV with a luminosity of 1034 cm-2s-1. This requires two beams, each with 2808 bunches. The nominal intensity per bunch is 1.1 1011 protons. The energy stored in each beam of 350 MJ could heat and melt 500 kg of copper. Protection of machine equipment in the presence of such powerful beams is essential. In this paper the mechanisms causing equipment damage in case of a failure of the machine protection system are discussed. An energetic heavy ion beam induces strong radial hydrodynamic motion in the target that drastically reduces the density in the beam heated region [*], leading to a much longer range for particles in the material. For the interaction of the LHC proton beams with a target a similar effect is expected. We carried out two-dimensional hydrodynamic simulations of the heating of a solid copper block with a face area of 2cm x 2cm irradiated by the LHC beam with nominal parameters. We estimate that after an impact of about 100 bunches the beam heated region has expanded drastically. The density in the inner 0.5 mm decreases by about a factor of 10. The temperature in this region is about 10 eV and the pressure about 15 GPa. The material in the heated region is in plasma state while the rest of the target is in a liquid state. The bulk of the following beam will not be absorbed and continue to tunnel further and further into the target. The results allow estimating the length of a sacrificial absorber, if such device should be installed for an LHC upgrade. A very interesting "spinoff" from this work would be the study of high-energy-density states of matter induced by the LHC beam, because a specific energy deposition of 200 kJ/g is achieved after 2.5 micros.

* N.Tahir et al., Phys. Rev. E, 63, 2001

 
 
MOPLT162 Continuous Abort Gap Cleaning at RHIC background, ion, accumulation, beam-losses 908
 
  • K.A. Drees, R.P. Fliller III, W. Fu, R. Michnoff
    BNL, Upton, Long Island, New York
  Since the RHIC Au-Au run in the year 2001 the 200 MHz cavity system was used at storage and a 28 MHz system during injection and acceleration.The rebucketing procedure potentially causes a higher debunching rate of heavy ion beams in addition to amplifying debunching due to other mechanisms. At the end of a four hour store, debunched beam can easily account for more than 30% of the total beam intensity. This effect is even stronger with the achieved high intensities of the RHIC run 2004. A beam abort at the presence of a lot of debunched beam bears the risk of magnet quenching and experimental detector damage due to uncontrolled beam losses. Thus it is desirable to avoid any accumulation of debunched beam from the beginning of each store, in particular to anticipate cases of unscheduled beam aborts due to a system failure. A combination of a fast transverse kicker and the new 2-stage copper collimator system is used to clean the abort gap continuously throughout the store with a repetition rate of 1 Hz. This report gives an overview of the new gap cleaning procedure and the achieved performance.  
 
MOPLT175 A Method to Measure the Focusing Properties (R_Matrix) of a Magnet focusing, ion, dipole, multipole 935
 
  • N. Tsoupas, L. Ahrens, K.A. Brown, D. Gassner, J. Glenn, Y.Y. Lee, T. Roser, P. Thieberger, J. Wei
    BNL, Upton, Long Island, New York
  We discuss a method that may be used to measure the focusing properties of a magnet. This method may prove valuable when applied to non-conventional magnets that deviate from the usual dipole magnets or other multipole magnets which are commonly used in a synchrotron. In this category of non-conventional magnets, fall special magnets, which come under the name Snakes. Such magnets are being used in synchrotron accelerators[*,**] to introduce artificial spin resonances to help overcome the intrinsic and/or imperfection spin resonances. This method of measuring the focusing properties of a magnet requires the use of low energy and high rigidity heavy-ions which may be obtained from the BNL Tandem accelerator.In brief the method consists on, injecting low emittance beamlets of lightly stripped heavy ions into a magnet and measuring the coordinates, of these narrowbeamlets, at the entrance and exit of the magnet.From the measurement of these coordinates of the narrowbeamlets we can deduce information on the R matrix and higher order matrix elements that define the focusing properties of the magnet.

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

 
 
TUXCH01 Review of ISOL-type Radioactive Beam Facilities ion, target, linac, ion-source 45
 
  • M. Lindroos
    CERN, Geneva
  The ISOL technique was invented in Copenhagen over 50 years ago and eventually migrated to CERN where a suitable proton drive beam was available at the Syncho-Cyclotron. The quick spread of the technique from CERN to many other laboratories has resulted in a large user community, which has assured the continued development of the method, physics in the front-line of fundamental research and the application of the method to many applied sciences. The technique is today established as one of the main techniques for on-line isotope production of high intensity and high quality beams. The thick targets used allows the production of unmatched high intensity radioactive beams. The fact that the ions are produced at rest makes it ideally suitable for low energy experiments and for post acceleration using well established accelerator techniques. The many different versions of the technique will be discussed and the many facilities spread all over the world will be reviewed. The major developments at the existing facilities and the challenges encountered will be presented. Finally, the possibility of using the resulting high intensity beams for the production of intense neutrino beams will be briefly discussed.  
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Transparencies
 
TUXCH02 FAIR - An International Accelerator Facility for Research with Ions and Antiprotons ion, antiproton, synchrotron, plasma 50
 
  • W.F. Henning
    GSI, Darmstadt
  This presentation describes the conceptual design for the accelerator facility and the physics research program, and discusses the status and the new challenges in accelerator physics and technology.  
Video of talk
Transparencies
 
TUPKF080 Photoemission Properties of Lead cathode, laser, electron, vacuum 1126
 
  • J. Smedley, T. Srinivasan-Rao, J. Warren
    BNL, Upton, Long Island, New York
  • R.S. Lefferts, A.R. Lipski
    SBUNSL, Stony Brook, New York
  • J. Sekutowicz
    Jefferson Lab, Newport News, Virginia
  There is significant interest in the possibility of building a super-conducting injector for high average current accelerator applications. One candidate for such a cavity design is superconducting lead. Such an injector would be made considerably simpler if it could be designed to use lead as the photocathode, eliminating the need for Cesiated materials in the injector. In this paper we present a study of the photoemission properties of lead at several UV wavelengths, including a study of the damage threshold of electroplated lead under laser cleaning. A quantum efficiency in excess of 0.1% has been achieved for a laser cleaned, electroplated lead sample with a laser wavelength of 193 nm.  
 
TUPLT015 The Bunch Compressor System for SIS18 at GSI ion, synchrotron, vacuum, impedance 1165
 
  • P. Hülsmann, G. Hutter, W. Vinzenz
    GSI, Darmstadt
  For bunch compression down to pulse durations of 50 ns, a dedicated rf system is under development for the SIS12/18 heavy ion synchrotron upgrade and will be described in this paper. Due to space restrictions in SIS12/18 the rf system consists of very short cavities which provide a very large voltage gradient (50 kV/m) at a very low frequency of approximately 800 kHz and rf final stages which provide a short rise time. The only possibilty to meet the requirements is the application of a cavity heavily inductively loaded by metallic alloy (MA) ring cores. This new rf system will be a prototype for the advanced acceleration and compression system needed in SIS100, which is the most important part for the proposed International Acceleration Facility at GSI. In order to gain experience with different MA ring core materials two of the four compressor cavities are loaded differently, which gives us an opportunity to learn the operational advantages of both materials. It is expected that the experimental results will support the final judgement for the future rf system in SIS100.  
 
TUPLT016 Improved Performance of the Heavy Ion Storage Ring ESR electron, ion, injection, storage-ring 1168
 
  • M. Steck, K. Beckert, P. Beller, B. Franczak, B.  Franzke, F. Nolden
    GSI, Darmstadt
  The heavy ion storage ring ESR at GSI allows experiments with stable and radioactive heavy ions over a large range of energies. The energy range available for operation with completely stripped ions has recently been extended to energies as low as 3 MeV/u. Even for bare uranium such low energies can be provided by deceleration of the ions which are stripped to high charge states in a foil at energies of 300-400 MeV/u. After injection the beam is cooled and decelerated in an inverse synchrotron mode interspersed with electron cooling at an intermediate energy. At the lowest energy of 3 MeV/u some hundreds of thousands ions could be electron cooled after deceleration. At energies of 10-20 MeV/u physics experiments with stored and slowly extracted beam have been performed with some million decelerated cooled ions. The cooling of radioactive ions by a combination of stochastic pre-cooling and final electron cooling has been demonstrated. The hot fragment beam, which was injected at an energy of 400 MeV/u, was cooled in about 6 s to a quality useful for precision experiments.  
 
TUPLT017 Achievements of the High Current Beam Performance of the GSI Unilac ion, emittance, rfq, injection 1171
 
  • W. Barth, L. Dahl, J. Glatz, L. Groening, S.G. Richter, S. Yaramishev
    GSI, Darmstadt
  The present GSI-accelerator complex is foreseen to serve for the future synchrotron SIS100 as an injector for up to 1012 U28+ particles/sec. The High Current Injector of the Unilac was successfully commissioned five years ago. An increase of more than two orders of magnitude in particle number for the heaviest elements in the SIS had to be gained. Since that time many different ion species were accelerated in routine operation. In 2001 a physics experiment used 2×109 Uranium ions per spill. In order to meet this request the MEVVA ion source provided for the first time in routine operation a high intense Uranium beam. The main purpose for the machine development program during the last two years was the enhancement of the intensity for Uranium beams. Different hardware measures and a huge investigation program in all Unilac-sections resulted in an increase of the uranium intensity by a factor of 7. The paper will focus on the measurements of beam quality, as beam emittance and bunch structure for Megawatt-Uranium beams. Additionally the proposed medium- and long-term hardware measures will be described, which should gain in the required uranium intensity to fill the SIS up to the space charge limit.  
 
TUPLT021 Heavy Ion Beam Transport in Plasma Channels plasma, ion, laser, beam-transport 1183
 
  • S. Neff, D.H. Hoffmann, R. Knobloch
    TU Darmstadt, Darmstadt
  • C. Niemann, D. Penache, A. Tauschwitz
    GSI, Darmstadt
  • S. Yu
    LBNL, Berkeley, California
  The transport of heavy ion beams in high current discharge channels is a promising option for the final beam transport in a heavy ion fusion reactor. The channel provides space-charge neutralization and an azimuthal magnetic field of several tesla, thereby allowing for transporting high current ion beams. The possibility to heat the hohlraum target with only two ion beams simplifies the reactor design significantly. Therefore channel transport is studied as part of the US fusion reactor study as an alternative to neutralized ballistic focusing. We have created 1 m long discharge channels and studied the channel development and stability. In addition, we have carried out proof-of-principle transport experiments using the UNILAC facility at the Gesellschaft für Schwerionenforschung. The experiments demonstrate the feasibility of plasma channel transport. Our transport experiments with low current beams are supplemented by simulations for high current beams. These simulations show the possibility of transporting particle currents of up to 60 kA.  
 
TUPLT027 Status of the HITRAP Decelerator Linac at GSI rfq, linac, ion, injection 1201
 
  • C.A. Kitegi, A. Bechtold, U. Ratzinger, A. Schempp
    IAP, Frankfurt-am-Main
  • T. Beier, L. Dahl, C. Kozhuharov, W. Quint, M. Steck
    GSI, Darmstadt
  • S. Minaev
    ITEP, Moscow
  Within the European Network HITRAP (heavy Ion trap) trapped and cooled higly charged ions up to U92+ will become avilable for a variety of attractive experiments in atomic physics. Heavy ions are produced, accelerated and stripped in the GSI accelerator complex and are stored in the ESR down to 4 MeV/u. To be captured in HITRAP, ions have to be decelerated to energies below 6 keV/u. The decelerator proposed to achieve these energies is a combination of an IH Drift tube cavity operating in the H11(0) mode and a RFQ. The operating frequency is 108.408MHz . The A/q range of the linac is up to 3. A very efficient deceleration by up to 11 MV along the 2.7 m long IH cavity with a rf power of 200kw is achieved by applying the KONUS beam dynamics. The deceleration from 500 A.keV down 6A.keV is provided by a 1.8 m long 4-rod RFQ.The beam dynamics as well as the cavity design of that linac will be described.The decelerator linac will be installed in the reinjection beam line and is being developed in collaboration between GSI and the Frankfurt University .  
 
TUPLT058 High Intensity Linac Driver for the SPIRAL-2 Project : Design of Superconducting 88 MHz Quarter Wave Resonators (beta 0.12), Power Couplers and Cryomodules linac, ion, quadrupole, resonance 1285
 
  • T. Junquera, J.-L. Biarrotte, S. Blivet, S. Bousson, C. Commeaux, G. Olry, H. Saugnac
    IPN, Orsay
  • P. Balleyguier
    CEA/DAM, Bruyères-le-Châtel
  • M. Fruneau, Y. Gomez-Martinez, E. Vernay, F. Vezzu
    LPSC, Grenoble
  A Superconducting Linac Driver, delivering deuterons with energy up to 40 MeV (5 mA) and heavy ions with energy of 14.5 MeV/u (1 mA ), is proposed for the Spiral-2 radioactive beams facility. For the high energy section of the linac, a superconducting 88 MHz Quarter Wave Resonator (beta 0.12) has been designed and the optimisation of RF and mechanical performances will be presented. Based on the present state-of-art of the Superconducting RF technology, maximum electric surface field of 40 MV/m and magnetic surface field of 80 mT, have been adopted which should allow to reach an accelerating field of 7 MV/m (energy gain 3 MeV per resonator). A first complete prototype is under construction. The high intensity deuteron beam specifications have imposed the design of an original power coupler (maximum power 20 KW). The RF, mechanical, and thermal characteristics will be presented. The design of the cryomodule for this high energy section, integrating two QWR with its associated equipments (couplers, tuners, helium tanks), will be presented.  
 
TUPLT102 Field Study of the 4T Superconducting Magnet for Rapid Cycling Heavy Ion Synchrotrons dipole, ion, synchrotron, simulation 1390
 
  • V.A. Mikhaylov, P.G. Akishin, A.V. Butenko, A.D. Kovalenko
    JINR, Dubna, Moscow Region
  The problem of the magnetic field optimization of a 4T dipole magnet with circular aperture of 100-110 mm for rapid cycling synchrotron is considered. A single layer low inductance coil made of hollow superconducting high current cable operating at 30 kA is used. The magnetic field ramp rate up to 4 T/s should be achievable. Mathematical method to minimize sextupole and higher order non-linearities to the tolerable values by variation of angular coil turn position is developed. The results of numerical simulation for 2D part magnetic field are presented. The further possibilities to improve the field quality for similar lattice magnets and their application for heavy ion synchrotrons and boosters are discussed.  
 
TUPLT105 Measurement of Activation Induced by an Argon Beam in a Copper Target at the SIS18 target, ion, radioactivity, radiation 1399
 
  • A. Fertman, A. Golubev, M. Prokuronov, B.Y. Sharkov
    ITEP, Moscow
  • G. Fehrenbacher, R.W. Hasse, I. Hofmann, E. Mustafin, D. Schardt, K. Weyrich
    GSI, Darmstadt
  Results of the measurement of activation induced by Argon beam with energies of E=100,200,800 MeV/u in the copper target are presented. The densities of various radioactive isotopes are derived from the measurements. Long-time prediction of radioactivity and accumulated doses in the accelerator equipment is calculated.  
 
TUPLT113 Technicalities for a Novel Medium Energy Ion Accelerator ion, positron, vacuum, proton 1411
 
  • V. Gorev
    RRC Kurchatov Institute, Moscow
  Transmutation of radioactive waste,high-intensity pulsed sources of fast neutrons,problem of inertially-confined fusion and a lot of different problems of science and technology put increased demands on the linear high power medium energy proton and heavy ion accelerators.But these accelerators are presently massive,huge and very expansive,which restrict now and in a near future their wide use and motivates the study of altenetive methods to achieve the design current,power and economic characteristics.This report decribes the present reseach on attaining high power medium energy ion beams,using novel idea for accelerator design.Theoretical proposal and preliminary conceptual design for the accelerator,based on a principle of free flying ion emitter("ballistic anode"),were discussed first a few years ago.The principle involves a high potencial difference generated only for a short time in the special vacuum chamber,but not steady-state conditions.Now,we would like to discuss next problems:1.technicalities of the ballistic anode design,both for proton and heavy ion beams generation.2 pulse power multiplication.3.high current sources for charge pumping of the ballistic anode.4 experimental modelling.  
 
TUPLT147 Multiple-charge-state Beam Steering in High-intensity Heavy-ion Linacs linac, emittance, focusing, beam-losses 1476
 
  • E.S. Lessner, P.N. Ostroumov
    ANL/Phys, Argonne, Illinois
  An algorithm suitable for correction to steering of multiple-charge-state beams in heavy-ion linacs operating at high currents has been developed [*]. It follows a four-dimensional minimization procedure that includes coupling of the transverse beam motions. A major requirement is that it obeys the restricted lattice design imposed by the acceleration of multiple-charge-state heavy-ion beams [**]. We study the algorithm efficiency in controlling the beam effective emittance growth in the presence of random misalignments of cavities and focusing elements. Limits on misalignments are determined by quantifying beam losses and effective steering requirements are selected by examining several correcting schemes within the real-state constraints. The algorithm is used to perform statistically significant simulations to study beam losses under realistic steering.

* E. S. Lessner and P. N. Ostroumov, Proc. Part. Accel. Conf. (2003)** P. N. Ostroumov, Phys. Rev. STAB Vol. 5, 0030101 (2002)

 
 
TUPLT181 Results of the First Run of the NASA Space Radiation Laboratory at BNL ion, booster, extraction, radiation 1550
 
  • K.A. Brown, L. Ahrens, J.M. Brennan, J. DeLong, C. Gardner, D. Gassner, J. Glenn, Y. Kotlyar, I. Marneris, A. Rusek, N. Tsoupas, K. Zeno
    BNL, Upton, Long Island, New York
  The NASA Space Radiation Laboratory (NSRL) was constructed in collaboration with NASA for the purpose of performing radiation effect studies for the NASA space program. The results of commissioning of this new facility were reported in [*]. In this report we will describe the results of the first run. The NSRL makes use of heavy ions in the range of 0.05 to 3 GeV/n slow extracted from BNL's AGS Booster. Many modes of operation were explored during the first run, demonstrating all the capabilities designed into the system. Heavy ion intensities from 100 particles per pulse up to $2×109$ particles per pulse were delivered to a large variety of experiments, providing a dose range up to 70 G/min over a 5x5 $cm2$ area. Results presented will include those related to the production of beams that are highly uniform in both the transverse and longitudinal planes of motion [**].

* K.A.Brown, et al, ‘‘Commissioning Results of Slow Extraction of Heavy Ions from the AGS Booster‘‘, Proceedings of the 2003 Particle Accelerator Conference, Portland, OR, 2003** N.Tsoupas, et al, ‘‘Commissioning of the Beam Transfer Line of the Booster Application Facility (BAF) at BNL'', These Proceedings

 
 
TUPLT184 Operational Measurement of Coupling by Skew Quadrupole Modulation coupling, quadrupole, injection, closed-orbit 1559
 
  • Y. Luo, P. Cameron, R. Lee, A. Marusic, F.C. Pilat, T. Roser, D. Trbojevic, J. Wei
    BNL, Upton, Long Island, New York
  The measurements of betatron coupling via skew quadrupole modulation is a new diagnostics technique that has been recently developed and tested at RHIC. By modulating the current of different skew quadrupole families with different frequencies and measuring the resulting eigentunes response with a high resolution phase lock loop (PLL) system, it is possible to determine the projections of the residual coupling coefficients. We report the results of extensive beam studies carried on at RHIC injection, store energy and on the ramp. The capability of measuring coupling on the ramp opens the possibility of continuous coupling corrections during acceleration.  
 
WEYCH03 Low and Medium Beta Superconducting Cavities linac, proton, ion, beam-loading 142
 
  • A. Facco
    INFN/LNL, Legnaro, Padova
  The use of low- and intermediate-beta superconducting cavities, once confined to low current heavy ion linacs, is steadily increasing in accelerators. The progress in this technology allowed a significant increase in cavity performance during the last 10 years; a large number of resonators, with different geometries, frequencies and gap numbers have been built for a large variety of applications and the development is still going on. The main boost is given by new projects of radioactive beam facilities and high power proton accelerators worldwide. While the advantages of SC resonators, compared with normal conducting structures, are rather well established in high-beta linacs, this is not always the case at low-beta. The choice of the optimum transition beam energy in a linac, where superconducting cavities should replace the room temperature ones, requires a careful evaluation that depends on the linac specifications.  
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WEPKF018 Beam-loss Induced Pressure Rise of LHC Collimator Materials Irradiated with 158 GeV/u In49+ Ions at the CERN SPS ion, vacuum, linac, beam-losses 1633
 
  • E. Mahner, I. Efthymiopoulos, J. Hansen, E. Page, H. Vincke
    CERN, Geneva
  During heavy ion operation, large pressure rises, up to a few orders of magnitude, were observed at CERN, GSI, and BNL. The dynamic pressure rises were triggered by lost beam ions that impacted onto the vacuum chamber walls and desorbed about 104 to 107 molecules per ion. The deterioration of the dynamic vacuum conditions can enhance charge-exchange beam losses and can lead to beam instabilities or even to beam abortion triggered by vacuum interlocks. Consequently, a dedicated measurement of heavy-ion induced molecular desorption in the GeV/u energy range is important for LHC ion operation. In 2003, a desorption experiment was installed at the SPS to measure the beam-loss induced pressure rise of potential LHC collimator materials. Samples of bare graphite, sputter coated (Cu, TiZrV) graphite, and 316 LN stainless steel, were irradiated under grazing angle with 158 GeV/u indium ions. After a description of the new experimental set-up, the results of the pressure rise measurements are presented, and the derived desorption yields are compared with data from other experiments.  
 
WEPLT055 Observation of Ultracold Heavy Ion Beams with Micrometer Size by Scraping ion, electron, emittance, storage-ring 1966
 
  • M. Steck, K. Beckert, P. Beller, B.  Franzke, F. Nolden
    GSI, Darmstadt
  The existence of an ordered beam state for low intensity, electron cooled heavy ion beams has been evidenced by a sudden reduction of the momentum spread. The detection of a similar effect in the transverse degree of freedom by non-destructive diagnostics is ruled out by the limited resolution of beam profile detectors. A method to probe the horizontal beam size of an electron cooled beam in a dispersive section has been developed. It is based on beam scraping and allows a resolution on the order of micrometers. This good transverse resolution for the cooled ion beam is achieved by precise changes of the ion energy which is varied by changes of the electron beam energy. The lower resolution limit due to power supply ripple is estimated to be below 1 micrometer. This method evidenced that the reduction of the momentum spread by one order of magnitude coincides with a reduction of the transverse beam emittance by 2-3 orders of magnitude, at least. A horizontal beam radius of a few micrometer could be demonstrated for electron cooled heavy ion beams with less than 1000 particles. This gives new evidence for the formation of an ordered beam arranged as a linear string of ions.  
 
WEPLT102 Electron Cooling Experiments at HIMAC Synchrotron ion, simulation, electron, injection 2089
 
  • K. Noda, T. Furukawa, T. Honma, S. Shibuya, D. Tan, T. Uesugi
    NIRS, Chiba-shi
  • T. Iwashima
    AEC, Chiba
  • I.N. Meshkov, E. Syresin
    JINR, Dubna, Moscow Region
  • S. Ninomiya
    RCNP, Osaka
  In the HIMAC synchrotron, the electron cooling experiments have been carried out since 2000 in order to develop new technologies in heavy-ion therapy and related research. Among of them, especially, the cool-stacking method has been studied to increase the intensity of heavy ions such as Fe and Ni in order to study the risk estimation of the radiation exposure in space. The simulation was carried out in order to optimize the stacking intensity under various the injection periods. In addition, the beam heating by the RF-KO and the clearing the secondary ion in the cooler were applied to avoid the instability occurred when the beam density became high. We will report the experiment results.  
 
WEPLT149 Image-charge Effects on the Beam Halo Formation and Beam Loss in a Small-aperture Alternating-gradient Focusing System beam-losses, focusing, lattice, quadrupole 2188
 
  • J. Zhou, C. Chen
    MIT/PSFC, Cambridge, Massachusetts
  The image-charge effects on an intense charged-particle beam propagating through an alternating-gradient focusing channel with a small aperture, circular, perfectly conducting pipe are studied using a test-particle model. For a well-matched elliptical beam with the Kapchinskij-Vladimirskij (KV) distribution, it is found that halo formation and beam loss is induced by nonlinear fields due to image charges on the wall. The halo formation and chaotic particle motion dependent sensitively on the system parameters: filling factor of the quadrupole focusing field, vacuum phase advance, beam perveance, and the ratio of the beam size to the aperture. Furthermore, the percentage of beam loss to the conductor wall is calculated as a function of propagating distance and aperture. The theoretical results are compared with PIC code simulation results.  
 
THOBLH01 Recent Improvement of Slow-extraction at HIMAC Synchrotron extraction, synchrotron, simulation, feedback 267
 
  • T. Furukawa, T. Furukawa, T.H. Uesugi
    Chiba University, Graduate School of Science and Technology, Chiba
  • T. Fujimoto, M. Kanazawa, K. Noda, S. Shibuya, E. Takada, S. Yamada
    NIRS, Chiba-shi
  • T. Naruse
    Seikei University, Graduate School of Engineering, Tokyo
  At HIMAC synchrotron, two kinds of slow-extraction method have been developed and utilized: third-order resonant slow-extraction and that with RF-knockout, not only for ion therapy but also for physics and biological experiments. Thus, the improvements of the extracted beam quality have also been carried out in both methods. One of the improvements is the global spill control. The global spill is improved owing to analytical approach in both methods. Cooperating with the feedback system, the flat spill is easily obtained without gain control of the feedback during the extraction. On the other hand, the effect of longitudinal motion for the bunched beam was studied to suppress the frequency component of the synchrotron oscillation in the spill ripple. Further, the transport of the extracted beam is readjusted for controlling the beam size. In this paper, recent improvement of slow-extraction at HIMAC is presented.  
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Transparencies
 
THPLT033 The Heavy Ion Gantry of the HICAT-facility ion, beam-transport, light-ion, dipole 2550
 
  • U. Weinrich, R. Fuchs
    GSI, Darmstadt
  • P. Emde
    MAN Technologie AG, Mainz
  The Heavy Ion Cancer Therapy Project HICAT at the University Hospital of Heidelberg is under construction. One unique feature of the treatment facility is the first heavy ion gantry in the world. The Gantry will allow the patient treatment with different ion species up to 430 MeV/u with full geometrical flexibility. This functionality has to be maintained for up to 300 000 rotations over the envisaged life cycle of 15 years. GSI has taken the responsibility to coordinate the design and construction of all the different required components. At the time of the conference the design will be finished and the construction started. The contribution will report on challenging construction items like the survey and alignment strategy, safety aspects, flexibility of the ion optics. In order to gain confidence on the principle a test bench with the last part of the gantry was already mounted in a fixed manner at GSI and beam measurements were performed. The results of these tests will also be reported.  
 
THPLT181 A Tomographic Technique for Magnetized Beam Matching electron, gun, linac, quadrupole 2876
 
  • C. Montag, I. Ben-Zvi, J. Kewisch
    BNL, Upton, Long Island, New York
  To maintain low electron beam temperatures in the proposed RHIC electron cooler, careful matching of the magnetized beam from the source to the cooler solenoid is mandatory. We propose a tomographic technique to diagnose matching conditions. First simulation results will be presented.