TUAZ  —  Joint Invited Parallel C+G (I)   (30-May-06   09:00—12:00)

Paper Title Page
TUAZ01 Overview of recent halo diagnosis and non-destructive beam profile monitoring 54
 
  • K. Wittenburg
    DESY, Hamburg
  
  Beam profile (emittance) and beam halo are characteristic properties of high-intensity and high energy beams that might limit the performance of the adjacent accelerator. Therefore a reliable measurement and determination of these parameters is most helpful for understanding, tuning and improvement of the whole accelerator chain to achieve the best (at least the design-) performance. This talk will give an overview over recent instruments used for non-destructive beam profile and halo monitoring and will discuss their limits, experiences and latest improvements.  
TUAZ02 High-Intensity Beam Collimation and Targetry 74
 
  • N. V. Mokhov
    Fermilab, Batavia, Illinois
  
  Principles, design criteria and realization are described for reliable collimation systems for the high-power accelerators (Fermilab Booster and Main Injector, SNS, J-PARC), hadron colliders (Tevatron and LHC) and e+e- linear colliders (ILC). Factors affecting the expected and achieved collimation performances are analyzed. Functionality of collimators as the key elements of the machine protection system are considered using as an example a recent beam accident case in the Tevatron. A substantial progress on the crystal collimation front is described. The key issues are considered in design of high-power target systems and achieving their best performance. Simulation code requirements and recent benchmarking results are presented. A status of conventional neutrino targets and neutrino factory target concepts is described along with performed and planned beam tests. Overview of the target and collimator material beam tests concludes this report.  
TUAZ03 The LHC beam collimation 0
 
  • S. Redaelli
    CERN, Geneva
  
  The Large Hadron Collider (LHC), presently under construction at the European Organization for Nuclear Research (CERN), will accelerate and collide 7 TeV proton beams with an unprecedented stored beam energy of 360 MJ. Handling this large stored energies in a superconducting machine requires a powerful collimation system which should provide a cleaning performance 100 to 1000 times better than what has been achieved in other operating storage rings. The LHC collimation system has also an important role in machine protection in case of system failures. Approximately 90 collimators with be available at the LHC from startup in order to fulfill these requirements. In this paper, the final LHC collimation system is presented. The designs of the various collimators is reviewed and the predicted performance of the overall system is discussed.  
TUAZ04 Safe disposal of the LHC beams by extraction onto the beam dumping blocks 0
 
  • B. Goddard
    CERN, Geneva
  
  The function of the LHC beam dumping system is to fast-extract the beam in a low-loss way from each ring of the collider and to transport it to an external absorber, positioned sufficiently far away to allow for appropriate beam dilution in order not to overheat the absorber material. Fast extraction will require a particle-free gap in the circulating beam, during which the field of the extraction kicker magnets can rise to its nominal value. Given the destructive power of the LHC beam, the dumping system must meet extremely high reliability criteria, which condition the overall and detailed design.  
TUAZ05 Comparison of Graphite and Diamond Structured Carbon Stripper Foils under Operational Conditions at the Los Alamos PSR 112
 
  • T. Spickermann, M. J. Borden, R. J. Macek
    LANL, Los Alamos, New Mexico
  • C. S. Feigerle
    University of Tennessee, Knoxville, Tennessee
  • R. W. Shaw
    ORNL, Oak Ridge, Tennessee
  • I. Sugai
    KEK, Ibaraki
  
  In the Los Alamos Proton Storage Ring H–Ions merge with circulating protons in a bending magnet and are stripped of their two electrons in a carbon stripper foil. The circulating protons continue to interact with the foil. Despite efforts to minimize the number of these foil hits, like “painting” of the vertical phase space, they can not totally be eliminated. As a result foil heating and radiation damage limit the lifetime of these foils. In recent years LANL has collaborated with KEK to improve the graphite foils in use at PSR and these foils now last typically for two months. Recently an alternative in the form of diamond structured carbon foils has been proposed for use at SNS. Depending on the grain size these are referred to as microcrystalline or nanocrystalline foils. Both types have been tested in PSR, with quite different results. While the microcrystalline foil failed catastrophically before production beam currents were reached the nanocrystalline foil was successfully used in normal operation for several weeks. Advantages of the diamond foil concept as well as some noteworthy differences that we observed with respect to the LANL graphite foils will be discussed here.  
TUAZ06 Development of hybrid typoe carbon stripper foils with high durability against 1800K for RCS of J-PARC 122
 
  • I. Sugai, Y. Arakida, Z. Igarashi, K. I. Ikegami, Y. Irie, H. Kawakami, M. Oyaizu, A. Takagi, Y. Takeda
    KEK, Ibaraki
  
  We have successfully made long-lived and hybrid , thick, boron mixed carbon stripper foils for high energy and high intensity accelerators. The foils were made by the controlled DC arc-discharge method, and the thickness is wide range from 50 to 600 ug/cm2. The lifetime of the foils was tested with use of 3.2 MeV Ne+DC beams of 2.5 uA, in which a significant of energy was deposited in the foils and thus we could simulate the condition by high power accelerator. The lifetime in maximum was shown to be extremely long, 102 and 410 times longer those of diamond and commercially available best carbon foils, respectively.