IPAC2011 - List of Authors (Calegari, D.)

Paper	Title	Page
TUPS017	The LHC Experimental Beam Pipe Neon Venting, Pumping and Conditioning	1557
	V. Baglin, G. Bregliozzi, D. Calegari, J.M. Jimenez, G. Lanza, G. Schneider CERN, Geneva, Switzerland
	The experimental vacuum chambers of the four LHC experiments (ATLAS, CMS, LHCb and ALICE) are mechanically optimized in order to be transparent to particles. In order to grant their mechanical stability and to avoid any overstress, every time there was a request for detector opening or closing and for working in the vicinity of the vacuum chamber, the experimental beam vacuum chambers have been vented to atmospheric pressure. Since the LHC start up a safety procedure has been applied to mechanically secure the four experimental beam pipes during each long technical stop. Ultra-pure neon was used to preserve at best the NEG pumping efficiency. Up to now more than 15 neon injections and pump down have been performed without detecting any reduction of the NEG efficiency. This paper describes the Gas Injection System performances and the main points of the venting and pumping procedure. Details of the experimental beam pipe vacuum recovery and conditioning are presented for each of the four LHC experiments (ATLAS, CMS, LHCb and ALICE).

Paper

Title

Page

The LHC Experimental Beam Pipe Neon Venting, Pumping and Conditioning

1557

V. Baglin, G. Bregliozzi, D. Calegari, J.M. Jimenez, G. Lanza, G. Schneider
CERN, Geneva, Switzerland

The experimental vacuum chambers of the four LHC experiments (ATLAS, CMS, LHCb and ALICE) are mechanically optimized in order to be transparent to particles. In order to grant their mechanical stability and to avoid any overstress, every time there was a request for detector opening or closing and for working in the vicinity of the vacuum chamber, the experimental beam vacuum chambers have been vented to atmospheric pressure. Since the LHC start up a safety procedure has been applied to mechanically secure the four experimental beam pipes during each long technical stop. Ultra-pure neon was used to preserve at best the NEG pumping efficiency. Up to now more than 15 neon injections and pump down have been performed without detecting any reduction of the NEG efficiency. This paper describes the Gas Injection System performances and the main points of the venting and pumping procedure. Details of the experimental beam pipe vacuum recovery and conditioning are presented for each of the four LHC experiments (ATLAS, CMS, LHCb and ALICE).