11 T dipole coil features and dimensions Christian Löffler and Emelie Nilsson 19/10/2016 11 T dipole coil features and dimensions

Outline Main parameters of the coil Nominal vs measurements Coil cross section – nominal vs inspected coil segment Cable insulation Include estimates on cable degradation

Tolerances on the coil Angle Loading Plate ±0.2°, nominal 18.387° Outer Radius ±0.15mm, nominal 60.8mm Azimuthal(AZ) Branch Length ±0.15mm, nominal 0.15mm AZ-Length is a function of the arc length and the outer diameter 0.1mm deviation is corresponding to a change of 15MPa in Coil Block 4, in AZ-Stress. This is confirmed by FEA, Mechanical Measurements and FUJI-paper analysis. Internal Reference: FEA version: 1607-1in1-cableV3_3; FUJI-Paper measurement: EDMS1726385

Results from previous coils For analysis coil separated in Ends, Center and Left and Right-Branch -> 4 values per coil Features analyzed LP-Angle Outer Radius Azimuthal Excess End 0-500mm Center 500-1000mm End 1000-1500mm

Results from previous coils Tolerances ± 0.2° End Center EDMS 1726385 Left-Branch Right-Branch Radial pressure distribution during pre-collaring of SP105, average over 10mm longitudinal. Measured with FUJI-Paper.

Results from previous coils Tolerances ±0.15mm Best-Fit of a non constrained circle on the measured point on the outer radius.

Results from previous coils Branch length 0.15mm Goal only in the very end of the straight section Azimuthal Excess Tolerances ±0.15mm

Comparison with coil segment coil #107 Nominal conductor position compared to the inspected cross section of a segment from coil #107 (photograph from MME) Deviation of radial position of inner layer blocks Reduced radial space between conductors near mid plane Due to over compression at some point (when closing the reaction/impregnation moulds)?

Image analysis on coil segment For MQXF: E. Rochepault et al. IEEE 2016 1. Detect cable contours 2. Fit them to trapezoids

Summary of analysis conductor growth Cables are curved on the middle  Fit 1/8 of the length near each end SEGMENT FROM COIL 107 Nominal (mm) Photograph + image analysis Tomography + image analysis (block 1 & 5) Tomography + image analysis Scheuerlein Width 14.85 (1%) 14.715 (0.1%) 14.787 (0.6%) 14.76 (0.4%) Mid thickness 1.306 (4.5%) 1.272 (1.8%) 1.322 (5.8%) 1.296 (3.7%) Uncertainties in measurement method and pixel sixe.

Cables seem to be systematically ‘bent’, in the upward direction MICA is C-shaped with an opening on the top side (coincidence?)

Cable insulation Nb3Sn Cable, Mica insulation, Glass Sleeved Insulation thickness (design values) MICA layer 0.080 mm Fibre braiding 0.075 mm Total insulation thickness 0.155 mm (0.100 mm under 30 MPa compression) Nb3Sn Cable, Mica insulation, Glass Sleeved

10 stack measurements insulation thickness Measurements show that the total insulation thickness in the range 110-115 μm. Tooling designed considering compression of the cable at 30 MPa with wall thickness of 100 μm. Original braiding: yarn count 14/2 cm (Coil 105-107, 110). Updated braiding: yarn count 12/2 cm. coil Ins thickness @ 30 Mpa (μm) 105 114 106 107 108 109 110 113 111 112 115 116 117 Original braiding 105 and 110 braifing gen 1 L yarn count 14/10 mm Updated braiding

Measurement of MICA thickness 10 layers of MICA piled up Thickness per layer of MICA: Measure 2: MICA between bare cables in 10-stack config.

Modify braiding parameters Attempt to reach design value 0.100 mm Insulation thickness S2 glass 11 TEX 636 [µm] S2-glass Braiding parameters # 1 11 T reference # 2 # 3 # 4 # 5 # 5b (with MICA) Yarn count/2 cm 12 18 17-18 No. of brins 9 6 5 4 32*9 11 TEX

Results 10-stack measurements Insulation thickness S2 glass 11 TEX 636 [µm] Pressure [MPa]  # 1 11T ref. # 2 # 3 # 4 # 5 # 5b (with MICA) 5 93 66 57 70 58 100 10 89 63 54 55 20 85 59 50 52 88 30 82 48 61 84 49 83 62 51 86 60 64 87 MICA adds ~35 um (Difference #5 to #5b) Samples to be produced and measured with MICA Prediction of # 4 (18 yarn counts/2 cm, 5 brins) with MICA : ~96 um # 4 (18 yarn counts/2 cm, 6 brins) : ~105 µm Plan to reach nominal with new braiding parameters (2nd generation short model). Also for 1st generation long coil?

Heat Treatment MICA layers to avoid gluing, removed after HT 1 layer 0.125 mm MP 1 layer of MICA 0.125 mm on OL 1 layer of MICA 0.125 mm on IL – tooling designed for 2 layers  Coil already oversized before heat treatment? Rmandrin = 29.75 mm Rcoil,inner = 30.0 mm Rcoil,outer = 60.6 mm LHCMBHST0009 Reaction tool LHCMBHST0009 At meeting: Better to use 2 layers (like in MQXF), is safer. Maybe not enough space?

Conclusion Short models produced: Segment of coil #107 analysed. 3/11 coils with outer radius within tolerances. 6/11 coils with loading plate angle within tolerances. 7/11 coils with azimuthal excess within tolerances. Coils are all azimuthally oversized! Segment of coil #107 analysed. Difficult to quantify cable dimensions. Visible radial deviation from nominal cable positions. To exclude effect from ‘cutting’, useful to look inside coil segment: tomographic measurements will be presented in talk later today. Strategy to reach design values of cable insulation (100 μm @ 30 Mpa) New braiding parameters are being explored. To be implemented for 2nd generation 11 T coil design. Interesting also for 1st generation long model?

Extra slides

Main parameters of the coil Coil: 56 turns, 2 layers, 6 blocks design, no internal splice Coil ID / OD 59.8 / 121.6 mm Coil overall length 5559 Straight section length 5108 Turns Inner Layer (IL) / Outer Layer (OL) 22 (IL) / 34 (OL) Impregnation System Epoxy DGEBA (CTD 101-K) Cable : RRP 0.7 mm dia. , 40 strands, cored, glass-mica insulated Cable Length (IL / OL / on spool) 235 (IL) / 364 (OL) / 680 m Cable bare width before / after reaction 14.7 / 14.85 (+1%) Cable bare mid-thickness before / after reaction 1.25 / 1.306 (+4.5%) Keystone angle before / after reaction 0.79 / 0.806 deg. Number of strands per cable (x strand diameter) 40 (x 0.7d [mm]) - Cable insulation wall thickness (design value) 0.1 Insulation Material Phlogopite + Glass