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MQXF coil cross-section status
Paolo Ferracin HiLumi WP3 Video-meeting 28 August, 2012
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Outline Update of MQXF coil cross-section with cable growth during reaction (from v2 to v3) Length of coil ends Paolo Ferracin 28/08/2012
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From HQ to MQXF: magnetic design concept (presented on July 26)
Aperture: from 120 mm to 150 mm Cable width: from 15 mm to 18 mm wide cable 2 layers with similar angles and 4 blocks All harmonics below 1 unit at 2/3 of Rin and 80% of Iss Similar iron geometry, but with OD from 520 mm to 558 mm HQ MQXF_v2 Paolo Ferracin 28/08/2012
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Cable and coil parameters (presented on July 26)
From HQ to MQXF Wider cable Increased insulation 43% more conductor HQ MQXF_v2 Units HQ MQXF_v2 Strand # 35 40 Width mm 15.150 18.273 Thickness in/out 1.338/1.536 1.396/1.604 Keystone angle 0.75 0.65 Insulation thickness 0.100 0.150 Mid-plane insulation 0.250 Interlayer insulation 0.500 Turns per oct. = 46 = 51 Area supercond. per oct. mm2 380 544 Paolo Ferracin 28/08/2012
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New cable dimensions Cable growth during reaction (unconfined heat treatment ) taken into account 2.0% in width 4.5% in mid-thickness Same keystone angle Similar inner layer Outer layer wedge slightly higher One turn less in outer layer Do we still want it? Or FRESCA2-type of layer jump? HQ MQXF_v3 Paolo Ferracin 28/08/2012
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Cable and coil parameters
HQ MQXF_v2 MQXF_v3 Units HQ MQXF_v2 MQXF_v3 Strand # 35 40 Width mm 15.150 18.273 18.638 Thickness in/out 1.338/1.536 1.396/1.604 1.462/1.673 Keystone angle 0.75 0.65 Insulation thickness 0.100 0.150 Mid-plane insulation 0.250 Interlayer insulation 0.500 Turns per oct. = 46 = 51 = 50 Area supercond. per oct. mm2 380 544 533 Paolo Ferracin 28/08/2012
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Conductor properties From 0.80 to 0.85 mm strand
Cu/Sc ratio: 1.13 (53% Cu) Assumption on Jc 2500 A/mm2 at 12 T 1400 A/mm2 at 15 T Resulting Jc for computations with self field correction 2650 A/mm2 at 12 T 1450 A/mm2 at 15 T Values consistent with D. Dietderich and H. Felice presentation and with FRESCA2 PIT strand data Paolo Ferracin 28/08/2012
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Stored energy / A ins_cable Differential inductance
Magnet parameters at 1.9 K HQ MQXF_v2 MQXF_v3 Units HQ MQXF_v2 MQXF_v3 Temperature K 1.9 Gradient T/m 170 140 Iss % % 81 80 Current kA 14.9 16.8 17.3 Peak field T 11.8 12.2 Stored energy MJ/m 0.86 1.41 1.44 Stored energy / A ins_cable J/cm3 93 104 102 Jo A/mm2 593 503 490 Differential inductance mH/m 7.10 8.68 8.27 Paolo Ferracin 28/08/2012
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Stress analysis Lorentz stress on mid-plane Bladder press. / interf.
HQ MQXF_v3 Lorentz stress on mid-plane IL: -101 MPa OL: -121 MPa Bladder press. / interf. 17 MPa / mm Max shell stress: 150 MPa Lorentz stress on mid-plane IL: -110 MPa OL: -126 MPa Bladder press. / interf. 27 MPa / mm Max shell stress: 229 MPa Paolo Ferracin 28/08/2012
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Stress analysis Coil peak stress
1.9 K -137 MPa 1.9 K -149 MPa Gnom -119 MPa Gnom -128 MPa Paolo Ferracin 28/08/2012
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Outline Update of MQXF coil cross-section with cable growth during reaction (from v2 to v3) Length of coil ends Paolo Ferracin 28/08/2012
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Estimate of MQXF length of coil ends
The HQ case Magnetic half-length 420 mm Coil half-length: 508 mm End length (return end) 90 mm The MQXF 90*(150/120) = 113 mm -> 120 mm Proposed “lengths of the region which includes everything between the portion of the magnet exceeding the magnetic length to the portion of the next magnet exceeding the magnetic length (R. De Maria)”, in the non-connection side 500 mm Paolo Ferracin 28/08/2012
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Estimate of MQXF length of coil ends
The HQ case End-shoe thickness ~40 mm End-shoe extension for NbTi-Nb3Sn splice ~150 mm MQXF (connection side) Can we incorporate the end plate in the NbTi-Nb3Sn splice extension (solution adopted in HD2/HD3)? Paolo Ferracin 28/08/2012
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Appendix Paolo Ferracin 28/08/2012
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From HQ to MQXF Mechanical design concept
Same support structure concept as HQ Same shell thickness, but OD from 570 mm to 608 mm Cooling holes and busbar slots added 10 mm thick LHe vessel included within 630 mm OD HQ MQXF Paolo Ferracin 28/08/2012
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Fringe field At 5 mm from the cryostat, fringe field ranging from 3 mT for HQ to 8 mT for MQXF HQ MQXF Paolo Ferracin 28/08/2012
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Stress analysis Lorentz stress on mid-plane Bladder press. / interf.
HQ MQXF_v2 Lorentz stress on mid-plane IL: -101 MPa OL: -121 MPa Bladder press. / interf. 17 MPa / mm Max shell stress: 150 MPa Lorentz stress on mid-plane IL: -113 MPa OL: -122 MPa Bladder press. / interf. 27 MPa / mm Max shell stress: 230 MPa Paolo Ferracin 28/08/2012
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Stress analysis Coil peak stress
1.9 K -137 MPa 1.9 K -150 MPa Gnom -119 MPa Gnom -129 MPa Paolo Ferracin 28/08/2012
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Some additional considerations on MQXF (II)
Cooling holes 80 mm diameter Could be increased to 90 mm, depending on axial support system Busbar 20 x 50 mm slot Axial support 32 mm axial rods Some space for end-plate and pad-bolts High stress but probably still fine Alternative: end-plate welded to vessel Paolo Ferracin 28/08/2012
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Some additional considerations on MQXF (III)
LHe vessel 10 mm thick cylinder OD: 630 mm 1 mm gap between vessel and Al shell (nominal dimension) About mm clearance after pre-loading, cool-down, and excitation Still to be verified the welding procedure Other modifications/simplifications Round collars? No masters? MQXF Paolo Ferracin 28/08/2012
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