| Title |
Systematic Measurement of the Pumping Capabilities of Cryogenic Surfaces |
| Authors |
- F. Chill, O.K. Kester
IAP, Frankfurt am Main, Germany
- L.H.J. Bozyk, O.K. Kester, P.J. Spiller
GSI, Darmstadt, Germany
|
| Abstract |
The quality of the beam vacuum is crucial for the stable operation of synchrotrons with high intensity heavy ions. Cryogenic surfaces are capable of pumping residual gases by cryocondensation until the saturated vapor pressure (SVP) is reached. Even at LHe temperatures the SVP of hydrogen is too high. If the surface coverage is sufficiently low, residual gas can also be bound by cryosorption, yielding in acceptable low pressures. These pumping capabilities can be described by two parameters, both dependent on surface temperature and coverage: The sticking probability (SP), that is the chance of an impinging gas particle to be bound, and the mean sojourn time (MST) of a particle on the surface. To acquire these parameters, an experimental setup is currently built at GSI. It consists of a cryogenic chamber, cooled by a cold head and a warm part with vacuum diagnostics and gas inlet. It allows monitoring the pumping speed and also the equilibrium pressure of the cryogenic part from which the SP and the MST can be deducted. The results will be used to further improve the accuracy of the dynamic vacuum simulations in cryogenic areas of particle accelerators.
|
| Paper |
download WEPME028.PDF [0.739 MB / 3 pages] |
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| Conference |
IPAC2014, Dresden, Germany |
| Series |
International Particle Accelerator Conference (5th) |
| Proceedings |
Link to full IPAC2014 Proccedings |
| Session |
Poster Session, Messi Area |
| Date |
18-Jun-14 16:00–18:00 |
| Main Classification |
07 Accelerator Technology Main Systems |
| Sub Classification |
T14 Vacuum Technology |
| Keywords |
radiation, cryogenics, vacuum, simulation, operation |
| Publisher |
JACoW Publishing, Geneva, Switzerland |
| Editors |
Christine Petit-Jean-Genaz (CERN, Geneva, Switzerland); Gianluigi Arduini (CERN, Geneva, Switzerland); Peter Michel (HZDR, Dresden, Germany); Volker RW Schaa (GSI, Darmstadt, Germany) |
| ISBN |
978-3-95450-132-8 |
| Published |
July 2014 |
| Copyright |
|
