P.Fabbricatore & S.Farinon Status of D2 development P.Fabbricatore & S.Farinon INFN Genova 2D Mechanical design 3D magnetic design Engineering studies

Configuration INFN_3_3_6 2D Lay-out Dx Dy R Rh

2D Magnetic Design I briefly remind that a 2D design magnetic design was performed in 2014 based on three pillars: No iron is placed in between the coils (so limiting saturation effects); Each coil is asymmetric in a way to cancel the magnetic cross talk each other. The yoke is suitably profiled for keeping constant the harmonic components

Main Characteristics 1 Characteristics Units Value Aperture mm 105 Number of apertures   2 Distance between apertures (cold/warm) 188.00/ 188.45 Cold mass outer diameter (min/max) 570/630 Magnetic length m 7.78 Bore field T 4.5 Peak field 5.20 Current kA 12.050 Temperature K 1.9 Loadline margin (%) 35 Overall current density A/mm2 443 Stored energy per meter MJ/m 0.2807 Differential inductance per meter mH/m 3.509 Stored energy MJ 2.18 Differential inductance mH 27.3

Main Characteristics 2 Characteristics Units Value Superconductor   Nb-Ti Strand diameter mm 0.825 Cu/No Cu 1.95 RRR >150 Superconductor current density at 10 T, 1.9 K A/mm2 2100 Number of strands per cable 36 Cable bare width 15.1 Cable bare mid thickness 1.480 Keystone angle degrees 0.90 Insulation thickness per side radial 0.160 Insulation thickness per side azimuthal 0.145 Number of layers 1 Number of turns 31=15+6+4+4+2 Cable unit length m 520 Coil physical length 8.2 Magnet physical length 8.5 Cold mass weigth t 17 Heat exchanger hole diameter 40 Heat exchanger angle 90 Heat exchanger distance from centre 237 Fx (per quarter, per aperture) [left right] MN/m 0.60/0.68 Fy (per quarter, per aperture) -0.40

b2 and b3 fine shim Adding a second hole, b2 and b3 are lowered of 2 and 1 unit respectively. This second hole could be filled with iron if not required

Lay-out and 2D mechanical design Last time we showed a solution with a single collar. Not satisfactory because the complexity of the assembly. However this solution is still there as plan B in case of major problems with a new double collar option. Mechanics: Single collar. An ‘old’ option still alive as plan B

New lay-out with a double collar option Aluminum alloy ring 6061-T6 or 7075-T6 made of short elements 50-100 mm. At room temperature the gap with collared coils is 0.2 mm Collars made of austenitic steel type YUS 130 S (Dl/l =2.6 10-3) Much better if we could use KHMN (Dl/l= 1.8 10-3) Centering the collared coils Centering the core with iron Collars with nose. It allows future coil modifications without changing the main collar structure Clamps and welded stiffening bars

plastic properties 0.6 mm gap winding collars Al alloy ring iron yoke [MPa] seqv sq (key zone) (nose zone) 2 collaring (F=386 tons/m) peak 212 -200 581 788 ̅ ave 85 -90 93 6 releasing pressure 213 -202 744 458 76 -81 54 8 closing of yoke (F=377 tons/m) 201 -209 833 716 289 114 78 -83 70 170 28 13 187 -176 809 401 222 384 77 -82 94 26 14 cool-down 149 -139 576 459 220 330 52 -52 43 12 15 energization to 4.5 T -103 560 331 218 221 -55 30 19

(studied on a previous version) Mechanical effects on b2 and b3 field harmonics (studied on a previous version)

Coil end design is 90% done End with connections

End with no connections

b3 (black) and a3 (red) components in the connection end Integrated harmonics still to be optimised (ex. b3 int. -5 unit in half coil with connection end )

Presently we have engineering drawings of the 2D cross section

Activity within the INFN project MAGIX 1) 2D magnetic design Jul 2014 2) 3D magnetic design (coil ends) Dec 2014 2) 2D mechanical design Dec 2014 3) Quench analysis Sep 2015 4) 3D mechanical design (axial pre-stress) Dec 2015 5) Enginering design of a short model Dec 2015 6) Engineering Design long Dec 2016 CERN General Schedule for D2

Conclusions The 2 D magnetic and mechanical designs were completed The 3D magnetic design is close to be completed Still to do: 3 D mechanical design, 3D engineering and Quench analyses