1. External Review of LHC Collimation Project Oliver Aberle 1th July 2004
Mechanical robustness

2. External Review of LHC Collimation Projects
Overview
Material choice
Ansys results
Material for phase 1
SPS test: Robustness
Beam parameters
Thermo-mechanical Analysis
Results
What can we learn?
External Review of LHC Collimation Projects

3. External Review of LHC Collimation Projects
Material choice
Which material withstands the different LHC beam scenarios?
External Review of LHC Collimation Projects

4. External Review of LHC Collimation Projects
Material choice
- Has to withstand 3 major scenarios:
Proton beam at 7 TeV (9.1e11 p, 200ns)
Beam at Injection (450 GeV, 3.2e13 p)
Ion beam (e.g. Pb)
- Other demands
Vacuum
Impedance
As before for “+” and “-”. +: No bonding technique (e.g. brazing) needed, cheap, independent of jaw material, easily replaceable (no need to throw away everything), compact, no penetrations. “-”: longer if “V” shaped is not used (but a “V-shape” would likely entail no “in-situ” spares).
External Review of LHC Collimation Projects

5. External Review of LHC Collimation Projects
Material choice
A: 10x10 mm
B: 5x5 mm
Finite Element Model
2D MESH
104 parabolic elements
3 104 nodes
0.05x0.05 mm mesh size
MATERIALS
Graphite
Beryllium
3D CFC
Graphite matrix with: 27 % in x direction 4 % in y and z direction
Elastic linear law
Small deformations
Free Sliding
Beam
sweeping
Symmetry
External Review of LHC Collimation Projects

6. External Review of LHC Collimation Projects
Ansys results
Graphite
Slice at 20 cm / 7 TeV
CFC
Slice at 100 cm / 450 GeV
External Review of LHC Collimation Projects

7. External Review of LHC Collimation Projects
Ansys results
Stress values for different proton load cases
Maximum stress values
External Review of LHC Collimation Projects

8. External Review of LHC Collimation Projects
Material for phase 1
Graphite or Carbon-carbon (very similar robustness?!)
10 times more robust than next best material (Be)
Beryllium does not withstand the expected beam impact at injection and 7 TeV (Ok for slow losses)
External Review of LHC Collimation Projects

9. External Review of LHC Collimation Projects
SPS test: Robustness
Vacuum tank
Beam axis
Support
Plug-in system
External Review of LHC Collimation Projects

10. External Review of LHC Collimation Projects
SPS test: Robustness
Full size horizontal collimator
Jaw length 1.2m
Jaw material CFC
Movement with LEP motors (2 per jaw)
Clamped jaws, water cooled
External Review of LHC Collimation Projects

11. External Review of LHC Collimation Projects
Beam parameters
Extraction of 4 × 72 bunches, 1.1 × 1011 protons each (2.4 MJ)
Robustness test with 5 shots 450 GeV, beam size 1 mm
External Review of LHC Collimation Projects

12. Thermo-mechanical Analysis
FEM Model for 3-D analysis
Contact elem. (Friction + Therm. Cond.)
Temperature dependent properties
Deposited Power (W/m3)
Pinned + Free exp. BC
Cooling pipes
Jaw material
Courtesy A. Bertarelli & R. Perret
External Review of LHC Collimation Projects

13. Thermo-mechanical Analysis
Dynamic stress – Preliminary estimation
Quasi-static Stress
Dynamic stress
External Review of LHC Collimation Projects

14. External Review of LHC Collimation Projects
Ansys results
Graphite R4550
Slice at 100 cm / 7 TeV
Graphite R4550
Sy = 20,7 MPa
A. Dallocchio & A. Bertarelli
External Review of LHC Collimation Projects

15. External Review of LHC Collimation Projects
Ansys results
CFC
Slice at 100 cm / 450 GeV
CFC AC150
Sy = 58,1 MPa
External Review of LHC Collimation Projects

16. External Review of LHC Collimation Projects
Ansys results
CFC
Slice at 100 cm / 450 GeV
Graphite R4550
Small deformations: ux = 6 mm
External Review of LHC Collimation Projects

17. External Review of LHC Collimation Projects
Ansys results
CFC
Slice at 100 cm / 450 GeV
Graphite R4550
Isotropic
A. Dallocchio & A. Bertarelli
External Review of LHC Collimation Projects

18. External Review of LHC Collimation Projects
What can we learn?
Robustness
Material properties (Fluka, Ansys)
Shower, energy
Vacuum behaviour
Collimator
Cooling
Shower, energy deposition (Fluka)
Impedance
Beam Settings
External Review of LHC Collimation Projects