1. 2 nd Joint HiLumi LHC – LARP Annual Meeting INFN Frascati – November 14 th to 16 th 2012 Helene Felice Paolo Ferracin LQ Mechanical Behavior Overview and Next Steps

2. Overview Magnet Overview 11/14/20122 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice Mechanical analysis and SG data comparison Next steps

3. LQ Design overview 90 mm aperture coils with Ti poles Iron pads, masters, yokes, Al shell Pre-load with bladders and keys LQS01-2 Short-sample limits (4.5 K – 1.9 K) – G ss : 240 T/m – 267 T/m – I ss : 13.8 kA – 15.4 kA – Peak field: 12.3 T - 13.6 T LQS03 Short sample limit – -G ss : 227 T/m – 250 T/m – I ss : 12.9 kA – 14.4 kA – Peak field: 11.5 T - 12.8 T End support: plate and rods Magnet/coil length: 3.7/3.4 m 11/14/20123 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice

4. LQ assembly Total of 60 gauges mounted (  and z) 20 on shell, 32 on coil poles, 8 on rods Four axial locations along coil length 11/14/20124 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice

5. LQ strain gauges Shell and coil stations –  and z gauges thermally compensated – 10 shell stations – 4 stations per coil 2 gauges/rod => 1 signal/rod Total of 60 gauges 11/14/20125 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice Measurements presented here are averages of the various gauges

6. Mechanical Analysis Typical Stress distribution Preload for 260 T/m   and   at 300 K - target (3D): + 56 MPa + 750    and   at 4.3 K - target (3D): + 183 MPa +2080     MPa  Shell Preload for 240 T/m: 471 kN  z and  z at 300 K - target (3D): +88 Mpa (178 kN) +455   z and  z at 4.3 K - target (3D): + 239 MPa + 1138  Rod End Contact pressure (Mpa) Preload for 260 T/m   and   at 300 K - target (3D): -82 MPa -580    and   at 4.3 K - target (3D): -157 MPa -1031      MPa  Pole NO gap 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 6

7. LQSD: structure validation 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 7 Loading and cool-down to 77K with aluminum dummy coils Validation of the structure behavior

8. LQS01a Summary Azimuthal stress LQS01a Gradient preload: 230-240 T/m Nominal Oversized From LQS01a to LQS01b Reduction of the radial shimming from 30 to 15 mils Fuji Test to confirm LQS01bLQS01a Some unloading of the pole suggested lack of preload 11/14/20128 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 30 mils ~ 750  m Radial shim thickness

9. LQS01b Summary Azimuthal stress LQS01a Gradient preload: 230-240 T/m LQS01b Gradient preload: 260-270T/m LQS01b loading required a bladder pressure of 8000 psi = 55 MPa 11/14/20129 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice Radial shim thickness 30 mils ~ 750  m 15 mils ~ 375  m

10. LQS02 Summary Azimuthal stress LQS01a Gradient preload: 230-240 T/m LQS01b Gradient preload: 260-270T/m LQS02 Gradient preload: 260-270 T/m 11/14/201210 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice Radial shim thickness 30 mils ~ 750  m 15 mils ~ 375  m

11. LQS03 assembly target and motivation LQS03 assembly target were chosen identical to LQS02 assembly targets Some uncertainty about the reason behind the lack of performance of LQS02 Concern about mid-plane block quenches - conservative approach in keeping the same preload -1-to-1 comparison with LQS02 – only change of conductor - Unloading of the pole can be handled by a “healthy magnet” => TQS03a 227 T/m 209 T/m 93% Iss 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 11

12. LQS03 Loading conditions 56 MPa -82 MPa 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 12 LQS01a Gradient preload: 230-240 T/m LQS01b Gradient preload: 260-270T/m LQS02 Gradient preload: 260-270 T/m LQS03 same preload as LQS02

13. Comparison of SG data during assembly

14. LQS01a SG shell data during assembly 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 14 57 +/- 8 MPa LQS03 LQS01b 34 +/- 8 MPa 67 +/- 6 MPa LQS02 56 +/- 8 MPa Shell SG behave consistently during assembly

15. SG Rod data during assembly 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 15 92 +/- 3 MPa LQS03 LQS01a 60 +/- 3 MPa 94 +/- 5 MPa LQS01b LQS02 92 +/- 2 MPa Rod SG behave consistently during assembly

16. SG Coil Pole pieces data 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 16 -77 +/- 21 MPa LQS01a LQS03 +5  12 MPa LQS01b LQS02 -107  26 MPa After LQS01a: -SG in compression -Large spread -69+/- 27 MPa

17. SG Comparison during cool-down

18. SG shell data during cool-down LQS03 LQS01aLQS01b LQS02 Shell SG behave consistently during cool-down 183+/- 9 MPa 199+/- 8 MPa 177+/- 9 MPa 147+/- 6 MPa 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 18

19. SG rod data during cool-down LQS03 LQS01aLQS01b LQS02 Rod SG behave consistently during cool- down 230+/- 10 MPa 235+/- 10 MPa 197+/- 11 MPa 239+/- 9 MPa LQS03 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 19

20. SG Coil Pole pieces data during cool-down LQS01a LQS01b LQS02 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 20 LQS03 -179+/- 104  -764+/- 372 

21. LQS03 SG Investigation No correlation in terms of station location No correlation in terms of coil No correlation between T and Z Amplitude of SG signals is inconsistent with magnet performance Impact on the magnet performance are unclear: No signs of mechanical motion recorded during training Temperature compensator might be in cause SG de-bonding? Might require a visual inspection 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 21

22. Excitation 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 22 LQS01a LQS01b LQS03 SG in tension still respond to excitation Slightly different rate of unloading observed from one coil to the other

23. LQS03 Warm up Shell and rods SG 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 23 495+/- 15  485+/- 15  716 +/- 101  584 +/- 101  Shell remains consistent Usual relaxation after the first test Rods recover their initial tension

24. LQS03 Warm up Coil pole SG 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 24 After warm-up, the SG do not recover the initial strain and still read some tension

25. LQ series: Summary on mechanical performance Trust in the capability of the structure to provide required preload: LQSD Linear unloading of the poles monitored by SG Shell and rods are behaving according to the FEM Absolute value of pole pieces SG cannot be trusted Challenge resides in the coil size and matching between pads and coil OD Impact on the magnet performance are unclear: No signs of mechanical motion recorded during training 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 25

26. Next steps Option 1: increase of preload Some concern: Risk of damaging the outer layer Mid-plane quenches in LQS02 Signs of pole unloading in LQS02 Limit in bladder pressure LQS03: 7500 psi (52 Mpa) Option 2 A this point: complete disassembly seems to be the way to learn something 3 to 4 months from magnet at LBL to magnet ready to be shipped to FNAL After disassembly: coil inspection – 2 possible outcomes: Signs of damage on the SG => repair => reassembly No sign of damage of the SG => ? 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 26