ALICE beampipe meeting 6 11 2013 Installation sequence

ALICE beampipe meeting 6. 11. 2013

Installation sequence Case A – we keep the central valve • TPC in parking position, old central pipe already removed • Install cage and central beampipe, align and bakeout • TPC in final position, miniframe in place • Install new ITS • Install and bakeout RB 24 pipe, open central valve 6/11/13 ALICE beampipe meeting 2

Installation sequence Case B – no central valve • TPC in parking position, old central pipe already removed • Install cage and central beampipe, align and check vacuum around flange • TPC in final position, miniframe in place • Install RB 24 pipe and bakeout both pipes • Install new ITS 6/11/13 ALICE beampipe meeting 3

Baseline design • Based on discussions with Cedric/Mark/Jaime • Bellows: based on sketch from Cedric • Bakeout sequence: discussions with Mark/Jaime 6/11/13 ALICE beampipe meeting 4

Baseline Layout new ALICE central beampipe (LS 2) V 4. 6 Central part A-side section C-side section IP 4236 444 4680 376 820 5500 20 13. 4 13 37. 2 40. 8 37. 2 13. 4 Bellow OD 60 α=15° OD 43 Support#2 155. 3 OD 43 OD 50 OD 80 Support#1 α=15° IP OD 36 η=3. 9 α=15° C-side Al section Central Be part OD 36 A-side Al section Support#3 96 19. 8 56 2584 3929. 8 4236 6/11/13 2600 26. 1 220 204. 3 330. 3 888 ALICE beampipe meeting 14 31. 7 376 All dimensions in mm. Wall thickness 800μm everywhere (bellow thickness 300μm) 5

Summary of tolerances Quantity Value Comment Construction and deflection 0. 6 mm LEB 21. 3. 12 Three support points Mechanical adjustment precision 1. 5 mm Survey to beamline uncertainty 1. 5 mm Quad fiducial to beamline uncertainty 0. 5 mm L 3 movement <0. 5 mm B field movement <0. 5 mm Linear sum 5. 1 mm RI 17. 2 n 1 13. 9 6/11/13 ALICE beampipe meeting LEB 22. 2. 12 2. 36σ/mm 6

n 1 (to be verified by Massimo) 6/11/13 ALICE beampipe meeting 7

Follow up from previous meeting With reference to the baseline layout, and assuming to have a fixed point on A-side: Ø Validate geometry of the bellows Study 2 load cases: – Load case #1 – during bakeout: +/- 1. 5 mm of radial displacement; 29 mm of compression due to bake-out (a pre-extension of the bellows can be considered to solve this issue) – Load case #2 – during run: +/- 6. 5 mm of radial displacement (+/- 5 mm coming from the displacement of the absorber - fatigue source); +/- 2. 5 mm of axial displacement (1. 5 mm of alignment + 1 mm of manufacturing tolerance) 6/11/13 ALICE beampipe meeting 8

Items to be studied • • • 1 st resonance frequency Compute deformation Verify aperture and impedance Background … 6/11/13 ALICE beampipe meeting 9

BACKUP 6/11/13 ALICE beampipe meeting 10

Sketch from C. Garion 22/05/2013 6/11/13 ALICE beampipe meeting 11

Corrected sketch after discussion with Jaime 23/10/2013 C-side Al section 37. 2 3 15 5 Al 5083 3 Al 2219 30 α=15° Bellow OD 60 OD 43 Bellow OD 60 OD 36 3 Al 5083 37. 2 Al 5083 α=15° 13 5 15 3 Al 2219 20 Al 5083 155. 3 Support#3 220 330. 3 31. 7 14 376 6/11/13 ALICE beampipe meeting 12

Considerations about clearance of the MFT planes from the pipe • The position of the MFT planes before the first bellow (and around the cylindrical pipe section) can be as close as 4 mm to the pipe (e. g. same radial distance as the innermost ITS layer 22 mm). • For the other planes one should consider the possible bellow deformations: Central beampipe mechanical adjustment precision = +-1. 5 mm Frontabsorber max. displacement = +-5 mm -------Worst case (see figure): 6. 5 mm displacement between central beampipe and C-side flange. MFT planes should not touch the pipe in this configuration. Measured beamline (2 mm from nominal) 5 mm 1. 5 mm Central beampipe 6/11/13 Frontabsorber ALICE beampipe meeting 13