Keyword: cryogenics
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TUP05 Prototype Room Temperature Quadrupole Chamber with Cryogenic Installations quadrupole, vacuum, simulation, synchrotron 75
 
  • S. Aumüller, L.H.J. Bozyk, P.J. Spiller
    GSI, Darmstadt, Germany
  • K. Blaum
    MPI-K, Heidelberg, Germany
 
  The synchrotron SIS100 at FAIR accelerator complex at the GSI Helmholtzzentrum will generate heavy ion beams of ultimate intensities. As medium charge states have to be used, the probability for charge exchange in collisions with residual gas particles of such ions is much lager than for higher charge states. In the last years, several measures have lowered the residual gas density to extreme high vacuum conditions. For example 55% of the circumference of SIS18 have already been coated with NEG, which provides high and distributed pumping speed. Nevertheless, this coating does not pump nobel and nobel-like components, which have very high ionization cross sections. A cryogenic environment at e.g. 50-80K provides a high pumping speed for all heavy residual gas particles. The only typical residual gas particle that cannot be pumped at this temperature is hydrogen. With the pumping speed of an additional NEG coating in these areas, the pumping will be optimized for all residual gas particles. The installation of cryogenic installations in the existing room temperature synchrotron SIS18 at GSI has been investigated. Measurements on a prototype chamber and simulations of SIS18 with cryogenic installations based on these measurements are presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP05  
About • Received ※ 21 June 2022 — Revised ※ 30 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUP06 Cryogenic Surfaces in a Room Temperature SIS18 Ioncatcher vacuum, heavy-ion, simulation, operation 79
 
  • L.H.J. Bozyk, S. Aumüller, P.J. Spiller
    GSI, Darmstadt, Germany
 
  For FAIR operation, the existing heavy ion synchrotron SIS18 at GSI will be used as booster for the future SIS100. In order to reach the intensity goals, medium charge state heavy ions will be used. Unfortunately, such ions have very high ionization cross sections in collisions with residual gas particles, yielding in beam loss and a subsequent pressure rise via ion impact stimulated gas desorption. To reduce the desorption yield, room temperature ioncatcher have been installed, which provide low desorption surfaces. Simulations including cryogenic surfaces show, that their high sticking probability prevents the vacuum system from pressure built-ups during operation. Such, the operation with heavy ion beams can be stabilized at higher heavy ion intensities, than solely with room temperature surfaces. A prototype ioncatcher containing cryogenic surfaces has been developed and built. The surfaces are cooled by a commercial coldhead, which easily allows this system being integrated into the room temperature synchrotron. The development and first laboratory tests including fast pressure measurements of this system will be presented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-HIAT2022-TUP06  
About • Received ※ 21 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 10 August 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)