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ALICE stability LEB meeting 21.03.2012 A. Behrens. Stability ALICE cavern. No deep references, cavern floor points or HLS sensor on the detector for stability information
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ALICE stability LEB meeting 21.03.2012 A. Behrens A. Behrens BE/ABP/SU-EM
Stability ALICE cavern • No deep references, cavern floor points or HLS sensor on the detector for stability information • BUT during network measurements of cavern wall brackets 2004, 2006 and 2007 and 2012 no significant vertical movements of cavern walls around the L3 magnet have been detected Front viewside A: Survey brackets on L3 foundation • O side • S4C • S6C • C side • Aside • O side • I side • S4M • S6M • L3M • L3C • I side • Top view: Survey brackets at beam level A. Behrens BE/ABP/SU-EM
Vertical position of surveybrackets • Reference measurements: • 17.07.2004 for brackets at beam level • 03.07.2007 for brackets on L3 foundation side A • Coordinate differences within +/- 0.4mm • With respect to survey precision no significant movement can be detected A. Behrens BE/ABP/SU-EM
Current central beampipeside A • Main support structure is Space Frame • Which supports also the TRD detector • TRD installation not yet finished A. Behrens BE/ABP/SU-EM
Stability central beampipeside A • Deformation of support structure due to detector installation • But will be finished in LS1 No stability prediction for future central beampipe by survey experience A. Behrens BE/ABP/SU-EM