MQXF support structure An extension of LARP experience Helene Felice MQXF Design Review December 10 th to 12 th, 2014 CERN

LQ Long Quadrupole LQS01a-b/02/03 LR Long Racetrack LRS01-02 HQ High-field Quadrupole HQ01a-b-c-d-e HQ02a-b / HQ03a Snapshot of LARP support structure experience 12/10/2014 Helene Felice2 Length Time m 1 m m SQ Subscale quad TQ Technology Quadrupole TQS01/02a-b-c/03a-b-c-d

LR Long Racetrack LRS01-02 Length demonstration LQ Long Quadrupole LQS01a-b/02/03 Some accelerator quality features Length with cos2  Accommodating variability in coil dimension HQ High-field Quadrupole HQ01a-b-c-d-e HQ02a-b / HQ03a Accelerator quality features Mechanical alignment Step-by-step technology demonstration 12/10/2014 Helene Felice3 Length Time m 1 m m SQ Subscale quad Concept TQ Technology Quadrupole TQS01/02a-b-c/03a-b-c-d Concept on cos2  Technology selection Scale-up & design optimization

LR Long Racetrack LRS01-02 Length demonstration LQ Long Quadrupole LQS01a-b/02/03 Some accelerator quality features Length with cos2  Accommodating variability in coil dimension HQ High-field Quadrupole HQ01a-b-c-d-e HQ02a-b / HQ03a Accelerator quality features Mechanical alignment High stress regime Exploration of the stress limits 12/10/2014 Helene Felice4 Length Time m 1 m m SQ Subscale quad Concept TQ Technology Quadrupole TQS01/02a-b-c/03a-b-c-d Concept on cos2  Technology selection Ultimate stress exploration Scale-up & design optimization

Outline Shell-based support structure concept Exploring the limits – TQ high stress Step-by-step technology demonstration – Design optimization – Length QXF support structure – Main features 12/10/2014Helene Felice5

Shell-based support structure Motivation and concept 12/10/2014 Helene Felice6 Shell-based support structure often referred as “bladder and keys” structure developed at LBNL for strain sensitive material coil pad shell

Shell-based support structure Supporting tools 12/10/2014 Helene Felice7 Numerical tools Instrumentation Assembly based on analysis Control of the pre-stress level Constant feedback between SG measurements and model

Shell-based support structure Concept 12/10/2014 Helene Felice8 Shell-based support structure often referred as “bladder and keys” structure developed at LBNL for strain sensitive material

Shell-based support structure Concept 12/10/2014 Helene Felice9 Displacement scaling 30 Shell-based support structure often referred as “bladder and keys” structure developed at LBNL for strain sensitive material Inflated Bladders Bladder

Shell-based support structure Concept 12/10/2014 Helene Felice10 Shell-based support structure often referred as “bladder and keys” structure developed at LBNL for strain sensitive material Displacement scaling 30 Shimming of the load leys Keys Bladder

Shell-based support structure Concept 12/10/2014 Helene Felice11 Shell-based support structure often referred as “bladder and keys” structure developed at LBNL for strain sensitive material Displacement scaling 30 Cool-down Keys Bladder

Shell-based support structure Concept 12/10/2014 Helene Felice12 Displacement scaling 30 Energized Shell-based support structure often referred as “bladder and keys” structure developed at LBNL for strain sensitive material Lorentz forces Cool-down Keys Bladder cold Room temperature Collaring process- Courtesy of Paolo Ferracin With shell structure Support structure allowing fine tuning of the

Shell-based support structure Key features Gradual application of the preload: no overshoot Tunable preload – During assembly – In between tests Reversible assembly process – Allowing replacement of a defective coil if needed Correlation between models and strain gauges measurements 12/10/2014Helene Felice13

Outline Shell-based support structure concept Exploring the limits – TQ high stress Step-by-step technology demonstration – Design optimization – Length QXF support structure – Main features 12/10/2014Helene Felice14

Stress limits: defining an acceptable range TQS03 program 12/10/2014 Helene Felice15 CONDUCTOR OST RRP 108/127 strand High RRR 54 % Cu fraction Jc (12T, 4.3 K) 2770 A/mm 2 27 strands cable 1.26 mm mid-thickness bare 10 mm width bare mm insulation TQS03 parameters 4.3 K1.9 K I ss (kA) B peak ss (T)1213 G ss (T/m) tests: TQS03 a, b, c and d performed with variable pre-stress TQS03a: 120 MPa TQS03b: 160 MPa TQS03c : 200 Mpa TQS03d: 120 MPa supported by ANSYS analysis

12/10/2014 Helene Felice16 Strain gauges location In boxes: sig theta measured Add predicted on box -160 MPa -120 MPa -190 MPa -110 MPa 200MPa 180MPa 160MPa Good agreement between measurements and ANSYS prediction

12/10/2014 Helene Felice17 93 % 91 % 88 % ~ 11.6 / 12.8 kA Only 5 % degradation from TQS03a to TQS03c TQS03d did not recover => Permanent degradation ~ 12 / 13.2 kA ~ 12.3 / 13.5 kA

Strain gauge data during excitation 12/10/2014 Helene Felice18 Strain gauge conclusion TQS03a TQS03b TQS03c Preload increase Correlation between preload levels and magnet performance allowed the definition of a safe range of transverse stress in Nb 3 Sn coils

Outline Shell-based support structure concept Exploring the limits – TQ high stress Step-by-step technology demonstration – Design optimization – Length QXF support structure – Main features 12/10/2014Helene Felice19

From TQ to HQ Design optimization 12/10/2014 Helene Felice20 TQLQ No alignment features Plot of stress along the length Optimization of the design load key positon Pad extremity in stainless steel to lower peak field in the end Implementation of alignment features from pad to shell

From TQ to HQ Design optimization: key position optimization 12/10/2014 Helene Felice21 TQ - 90 mm aperture - 12 T peak field T/m - F  Layer 1 = -1.5 MN/m - F  Layer 2 = MN/m LQ - 90 mm aperture - 12 T peak field T/m - F  Layer 1 = -1.5 MN/m - F  Layer 2 = MN/m -100 MPa -187 MPa -85 MPa -171 MPa Key optimization => Optimization of the key position to improve stress distribution 20 MPa

From TQ to HQ Design optimization 12/10/2014 Helene Felice22 TQLQHQ No alignment features Cross-section optimization considering force distribution between layers Alignment features between coil and pads: aluminum collars and key Optimization of the design load key positon Pad extremity in stainless steel to lower peak field in the end Implementation of alignment features from pad to shell

From TQ to HQ Design optimization: key position optimization 12/10/2014 Helene Felice23 TQ - 90 mm aperture - 12 T peak field at 4.3 K T/m - F  Layer 1 = -1.5 MN/m - F  Layer 2 = MN/m LQ - 90 mm aperture - 12 T peak field at 4.3 K T/m - F  Layer 1 = -1.5 MN/m - F  Layer 2 = MN/m HQ mm aperture - 14 T peak field at 4.3 K T/m - F  Layer 1 = MN/m - F  Layer 2 = MN/m -100 MPa -187 MPa -85 MPa -171 MPa MPa Xsection optimization Key optimization => Improvement of the cross-section to avoid layer 2 overloading 20 MPa MPa

12/10/2014 Helene Felice24

Stress in HQ 12/10/2014 Helene Felice25 Adresses: -Stress distribution -2D and 3D -Pad ss and iron -Ground for MQXF stress level

Outline Shell-based support structure concept Exploring the limits – TQ high stress Step-by-step technology demonstration – Design Optimization – Length QXF support structure – Main features 12/10/2014Helene Felice26

1 st long shell based structure: the Long Racetrack LR 12/10/2014 Helene Felice27 LRS01: full length shell Friction limits the shell contractions Central part locked Strain at 4.5 K consistent with 0.2 friction model results During excitation e.m. forces induced slippage Magnet parameters

Impact of shell segmentation 12/10/2014 Helene Felice#28 LRS01 – High meas. axial strain meas. – Effect on azimuthal stress LRS02 (with segmented shell) – Reduced axial strain LRS LQS LRS01 LRS02

Length demonstration on a cos2  magnet: the Long Quad LQ 12/10/2014 Helene Felice29 90 mm aperture coils with Ti poles Iron pads, masters, yokes, Al shell Pre-load with bladders and keys TQ coil scale-up 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

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 Mechanical Analysis Typical Stress distribution 12/10/2014 Helene Felice30 Preload for 260 T/m   and   at 300 K - target (3D): + 56 MPa    and   at 4.3 K - target (3D): MPa     MPa  Shell NO gap

Axial strain in shell 12/10/2014 Helene Felice31

Production readiness: Accommodating coil size variation 12/10/2014 Helene Felice32 Expected measured shell Strain Gauge coil Strain Gauge Nominal pad Pole Strain Gauge LQS01a Nominal Oversized pad Pole Strain Gauge 92 % at 4.5 K LQS01aLQS01b

Outline Shell-based support structure concept Exploring the limits – TQ high stress Step-by-step technology demonstration – Alignment features – Length QXF support structure – Main features 12/10/2014Helene Felice33

From LARP to MQXF 12/10/2014 Helene Felice34

MQXF support structure overview 12/10/2014 Helene Felice35 Show how the key features described before are found in MQXF support structure design Point to Mariusz’s talk