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Wallén, E. J.

Paper Title Page
TUPC119 Corrector Based Determination of Quadrupole Centres 1347
 
  • M. Sjöström, M. Eriksson, L.-J. Lindgren, E. J. Wallén
    MAX-lab, Lund
  
  A corrector magnet based method to determine the quadrupole magnet centres for storage rings has been tested on the MAX III synchrotron light source. The required corrector magnet strengths for the corrected beam orbit are used to determine the quadrupole magnet centre positions. This method is the most effective for an optimal distribution of beam position monitors and corrector magnets in the storage ring and will be used as a basis for the MAX IV storage rings.  
WEPC011 Using Multi-bend Achromats in Synchrotron Radiation Sources 2007
 
  • M. Eriksson, A. Hansson, S. C. Leemann, L.-J. Lindgren, M. Sjöström, E. J. Wallén
    MAX-lab, Lund
  • L. Rivkin, A. Streun
    PSI, Villigen
  
  Multi-bend achromats offer small electron beam emittance, large energy acceptance and a good dynamic aperture. Two examples are discussed in the article, each using 7-bend achromats; a 12 achromat lattice and a 20 achromat one. Some possible technical solutions associated with the dense lattices are discussed: magnet technology, vacuum system and RF system. Some characteristics of the two rings are also presented; effects of Intra Beam Scattering, Touschek life-time and the electron beam parameter values.  
WEPC103 Design of a Cold Vacuum Chamber for Diagnostics 2240
 
  • S. Casalbuoni, T. Baumbach, A. W. Grau, M. Hagelstein, R. Rossmanith
    FZK, Karlsruhe
  • V. Baglin, B. Jenninger
    CERN, Geneva
  • R. Cimino
    INFN/LNF, Frascati (Roma)
  • M. P. Cox
    Diamond, Oxfordshire
  • E. M. Mashkina
    University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
  • E. J. Wallén
    MAX-lab, Lund
  • R. Weigel
    Max-Planck Institute for Metal Research, Stuttgart
  
  Preliminary studies performed with the cold bore superconducting undulator installed in the ANKA storage ring suggest that the beam heat load is mainly due to the electron wall bombardment. Low energy electrons (few eV) are accelerated by the electric field of the beam to the wall of the vacuum chamber, induce non-thermal outgassing from the cryogenic surface and heat the undulator. In this contribution we report on the design of a cold vacuum chamber for diagnostics to be installed in the ANKA (ANgstrom source KArlsruhe) storage ring and possibly in third generation light sources. The diagnostics implemented are:
  1. retarding field analyzers to measure the electron energy and flux,
  2. temperature sensors to measure the total heat load,
  3. pressure gauges,
  4. and a mass spectrometer to measure the gas content.
The aim of this device is to gain a deeper understanding on the heat load mechanisms to a cold vacuum chamber in a storage ring and find effective remedies. The outcome of the study is of relevance for the design and operation of cold bore superconducting insertion devices in synchrotron light sources. 		 
THPP141 Test of a NEG Coated Copper Dipole Vacuum Chamber 3693
 
  • E. J. Wallén, M. Berglund, A. Hansson
    MAX-lab, Lund
  • R. Kersevan
    ESRF, Grenoble
  
  The paper reports about a test carried out at the 1.5 GeV storage ring MAX II where a standard dipole chamber made of stainless steel was replaced by a NEG coated chamber made of copper. The standard MAX II stainless steel dipole vacuum chamber is connected to an ion pump and a sublimation pump while the NEG-coated copper dipole vacuum chamber has no additional pumps. The NEG-coated dipole chamber made of copper has been demonstrated to work well with a stable vacuum level in the region where it is installed. The coating procedure for the bent dipole chamber copper tube is slightly more complicated than the coating procedure for a straight chamber of similar size due to its curvature and lack of line-of-sight. The procedure is also described in some detail. The main motivation for the interest in NEG-coated vacuum tubes is the reduced cost of the vacuum system and also the possibility to build more slender vacuum systems, thus simplifying and optimizing the design of accelerator magnet systems.