Author: Kollmus, H.
Paper Title Page
MOPRI105 Heavy Ion Induced Desorption Measurements on Cryogenic Targets 867
SUSPSNE045   use link to see paper's listing under its alternate paper code  
 
  • Ch. Maurer, D.H.H. Hoffmann
    TU Darmstadt, Darmstadt, Germany
  • L.H.J. Bozyk, H. Kollmus, Ch. Maurer, P.J. Spiller
    GSI, Darmstadt, Germany
  
  Funding: Bundesministerium für Bildung und Forschung FKZ 06DA7031
Heavy-ion impact induced gas desorption is the key process that drives beam intensity limiting dynamic vacuum losses. Minimizing this effect, by providing low desorption yield surfaces, is an important issue for maintaining a stable ultra high vacuum during operation with medium charge state heavy ions. For room temperature targets, investigation shows a scaling of the desorption yield with the beam's near-surface electronic energy loss, i.e. a decrease with increasing energy*,**. An optimized material for a room temperature ion-catcher has been found. But for the planned superconducting heavy-ion synchrotron SIS100 at the FAIR accelerator complex, the ion catcher system has to work in a cryogenic environment. Desorption measurements with the prototype cryocatcher for SIS100 showed an unexpected energy scaling***, which needs to be explained. Understanding this scaling might lead to a better suited choice of material, resulting in a lower desorption yield. An experimental setup for systematic examination of this scaling is presented. The cryogenic beam-induced desorption yield of several materials at different temperatures is examined.
* H. Kollmus et al., AIP Conf. Proc. 773, 207 (2005))
** E. Mahner et al., Phys. Rev. ST Accel. Beams 14, 050102 (2011)
*** L.H.J. Bozyk, H. Kollmus, P.J. Spiller, Proc. of IPAC 2012, p. 3239 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI105  
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WEOBA01 Status of the FAIR Synchrotron Projects SIS18 Upgrade and SIS100 1857
 
  • P.J. Spiller, R. Balß, A. Bleile, L.H.J. Bozyk, J. Ceballos Velasco, T. Eisel, E.S. Fischer, P. Forck, P. Hülsmann, M. Kauschke, O.K. Kester, H. Klingbeil, H.G. König, H. Kollmus, P. Kowina, A. Krämer, J.P. Meier, A. Mierau, C. Omet, D. Ondreka, N. Pyka, H. Ramakers, P. Schnizer, H. Welker, St. Wilfert
    GSI, Darmstadt, Germany
  • A. Iluk
    WRUT, Wrocław, Poland
  • H.G. Khodzhibagiyan
    JINR, Dubna, Moscow Region, Russia
  • D. Urner
    FAIR, Darmstadt, Germany
  
  The upgrade of the existing heavy ion synchrotron SIS18 as booster for the FAIR synchrotron SIS100 has been partly completed. With the achieved technical status, a major increase of the accelerated number of heavy ions could be reached. This progress especially demonstrates the feasibilty of acceleration of medium charge state heavy ions with high intensity and and the succesfull control of dynamic vaccuum effects and correlated charge exchange loss. Two further upgrade measures, the installation of additional MA acceleration cavities and the exchange of the main dipole power converter are in progress. For the FAIR synchrotron SIS100 all major components with long production times have been ordered. With several pre-series components, outstanding technical developments have been completed and the readiness for series production reached. The technical project status will be summarized.  
slides icon Slides WEOBA01 [6.107 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEOBA01  
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