Regensburg 2000 – wissenschaftliches Programm
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VA: Vakuumphysik und Vakuumtechnik
VA 3: Vakuumtechnik
VA 3.1: Vortrag
Montag, 27. März 2000, 17:20–17:40, H\"orsaal 47
Fast Shutters for the Vacuum System of LEP — •Willemjan Maan, Oscar Andujar, Patrick Coly, Paul Cruikshank, and Wilhelmus Koelemeijer — CERN, LHC Division, 1211 Geneva, Switzerland
As part of the upgrading of the LEP accelerator to higher beam energies, fast shutters were procured to protect the super conductive cavities from accidental loss of the ultra high vacuum due to leaks or particles generated by the implosion of the thin wall experimental chambers.
The specification for this DN100 fast shutter is a closure time within 20 ms, a leak rate over the valve seat less than 1.5 10−2 Pa m3 s−1 with a differential pressure of 105 Pa, a radiation resistance up to 100 Gy and small internal section changes to minimize beam induced losses.
The fast shutters exhibited a number of difficulties during the commissioning period. After several modifications, which are described in this paper, 16 shutters were reinstalled during the 1998-1999 shutdown.
Functionality problems, modifications and final performance will be described, including the control system used to detect vacuum pressure changes and the trigger for the closing of the fast shutters.