2 nd joint hilumi lhc – larp annual meeting infn frascati – november 14 th to 16 th 2012 helene...
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2nd Joint HiLumi LHC – LARP Annual MeetingINFN Frascati – November 14th to 16th 2012
Helene FelicePaolo Ferracin
LQ Mechanical Behavior Overviewand Next Steps
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Overview
• Magnet Overview
11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
• Mechanical analysis and SG data comparison
• Next steps
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Mea
sure
d St
ress
(M
Pa) LQS01a - shell
LQS01a - PoleT
LQS01b - shell
LQS01b - PoleT
LQS02 - shell
LQS02 - PoleT
LQS03 - shell
LQS03 - PoleT
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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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)– Gss: 240 T/m – 267 T/m
– Iss: 13.8 kA – 15.4 kA– Peak field: 12.3 T - 13.6 T
• LQS03 Short sample limit– -Gss: 227 T/m – 250 T/m
– Iss: 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
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LQ assembly
• Total of 60 gauges mounted (q and z)• 20 on shell, 32 on coil poles, 8 on rods• Four axial locations along coil length
11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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LQ strain gauges
• Shell and coil stations– q and z gauges thermally
compensated– 10 shell stations– 4 stations per coil
• 2 gauges/rod => 1 signal/rod• Total of 60 gauges
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Measurements presented here are averages of the various gauges
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Mechanical AnalysisTypical Stress distribution
Preload for 260 T/msq and eq at 300 K- target (3D): + 56 MPa
+ 750 mesq and eq at 4.3 K- target (3D): + 183 MPa
+2080 me
s q (MPa)
Shell
Preload for 240 T/m: 471 kNsz and ez at 300 K- target (3D): +88 Mpa (178 kN)
+455 mesz and ez at 4.3 K- target (3D): + 239 MPa
+ 1138 me
Rod
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-0.2 0 0.2 0.4 0.6 0.8 1
End
cont
act p
ress
ure
(MPa
)
Fem/Fem_240T/m
293 K
End
Cont
act p
ress
ure
(Mpa
)
Preload for 260 T/msq and eq at 300 K - target (3D): -82 MPa
-580 mesq and eq at 4.3 K - target (3D): -157 MPa
-1031 me s q (MPa)
Pole
NO gap
11/14/2012 2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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LQSD: structure validation
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• Loading and cool-down to 77K with aluminum dummy coils
• Validation of the structure behavior
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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Mea
sure
d St
ress
(M
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LQS01a - shell
LQS01a - PoleT
LQS01a SummaryAzimuthal stress
LQS01a Gradient preload: 230-240 T/m
Nominal Oversized
From LQS01a to LQS01bReduction of the radial shimming from 30 to 15 mils
Fuji Test to confirm
LQS01b LQS01a
Some unloading of the pole suggested lack of preload
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30 mils ~ 750 mm
Radial shim thickness
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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LQS01b SummaryAzimuthal stress
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LQS01a - shell
LQS01a - PoleT
LQS01b - shell
LQS01b - PoleT
LQS01a Gradient preload: 230-240 T/mLQS01b Gradient preload: 260-270T/m
LQS01b loading required a bladder pressure of 8000 psi = 55 MPa
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Radial shim thickness
30 mils ~ 750 mm
15 mils ~ 375 mm
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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LQS02 SummaryAzimuthal stress
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LQS01a - shell
LQS01a - PoleT
LQS01b - shell
LQS01b - PoleT
LQS02 - shell
LQS02 - PoleT
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0 100 200 300 400 500 600 700 800 900 1000 1100Co
il az
imut
hal m
icro
stra
in
Shell azimuthal microstrain
Oversized coil 2DNominal 3DLQS01a before cool-down LQS01b loadingLQS02a loading
LQS01a Gradient preload: 230-240 T/mLQS01b Gradient preload: 260-270T/mLQS02 Gradient preload: 260-270 T/m
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Radial shim thickness
30 mils ~ 750 mm
15 mils ~ 375 mm15 mils ~ 375 mm
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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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
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Imag
(A)
Training Quench #
LQS01a - 4.5 K LQS01a - 3.1 KLQS01a - 4.3 K LQS01a - 1.9 KLQS01b - 4.5 K LQS01b - 3 KLQS01b - 1.9 K LQS01b - 2.3 - 4KLQS02a - 20 A/s - 4.5 K LQS02a - ramp-rate - 4.5 KLQS02a - ramp-rate - 2.6 K LQS02a - ramp-rate - 1.9 K
227 T/m
209 T/m93% Iss
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2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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LQS03 Loading conditions
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Mea
sure
d St
ress
(M
Pa) LQS01a - shell
LQS01a - PoleT
LQS01b - shell
LQS01b - PoleT
LQS02 - shell
LQS02 - PoleT
LQS03 - shell
LQS03 - PoleT
56 MPa
-82 MPa
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LQS01a Gradient preload: 230-240 T/mLQS01b Gradient preload: 260-270T/mLQS02 Gradient preload: 260-270 T/mLQS03 same preload as LQS02
Comparison of SG data during assembly
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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LQS01a
SG shell data during assembly
11/14/2012
57 +/- 8 MPa
LQS03
LQS01b
34 +/- 8 MPa67 +/- 6 MPa
LQS02
56 +/- 8 MPaShell SG behave
consistently during
assembly
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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SG Rod data during assembly
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92 +/- 3 MPa
LQS03
LQS01a
60 +/- 3 MPa 94 +/- 5 MPa
LQS01b
LQS02
92 +/- 2 MPaRod SG behave
consistently during
assembly
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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SG Coil Pole pieces data
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-77 +/- 21 MPa
LQS01a
LQS03
+5 12 MPa
LQS01b
LQS02
-107 26 MPa
After LQS01a:-SG in compression-Large spread
-69+/- 27 MPa
SG Comparison during cool-down
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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SG shell data during cool-down
LQS03
LQS01a LQS01b
LQS02
Shell SG behave consistently
during cool-down
183+/- 9 MPa
199+/- 8 MPa
177+/- 9 MPa
147+/- 6 MPa
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2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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SG rod data during cool-down
LQS03
LQS01a LQS01b
LQS02
Rod SG behave
consistently during cool-
down
230+/- 10 MPa
235+/- 10 MPa
197+/- 11 MPa
239+/- 9 MPa
LQS03
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2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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SG Coil Pole pieces data during cool-down
LQS01a
LQS01b
LQS02
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LQS03
-179+/- 104 me
-764+/- 372 me
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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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
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2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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Excitation
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LQS01a
LQS01b
LQS03• SG in tension still respond to
excitation• Slightly different rate of
unloading observed from one coil to the other
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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Rod
axia
l str
ain
(me)
ROD A
ROD B
ROD C
ROD D
LQS03 Warm upShell and rods SG
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495+/- 15 me485+/- 15 me
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Shel
l Azi
m s
trai
n (me) S1RT
S1LT
S2TT
S2RT
S2BT
S2LT
S3RT
S3LT
S4TT
S4BT716 +/- 101 me 584 +/- 101 me
Shell remains consistentUsual relaxation after the first test
Rods recover their initial tension
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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LQS03 Warm upCoil pole SG
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• After warm-up, the SG do not recover the initial strain and still read some tension
2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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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
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2nd Joint HiLumi LHC - LARP Annual Meeting - H. Felice
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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