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

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

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 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 T End support: plate and rods Magnet/coil length: 3.7/3.4 m 11/14/ nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice

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/ nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice

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/ nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice Measurements presented here are averages of the various gauges

Mechanical Analysis Typical Stress distribution Preload for 260 T/m   and   at 300 K - target (3D): + 56 MPa    and   at 4.3 K - target (3D): MPa     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): MPa  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      MPa  Pole NO gap 11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 6

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

LQS01a Summary Azimuthal stress LQS01a Gradient preload: 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/ nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice 30 mils ~ 750  m Radial shim thickness

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

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

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

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

Comparison of SG data during assembly

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

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

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

SG Comparison during cool-down

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

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

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

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

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

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

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

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

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