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HL-LHC Corrector Magnet Design & Construction Activity Status. Giovanni Volpini on behalf of the LASA team CERN, January 14 2014. summary. Magnet specs requirements: integrated field, radiation loads & material certification operating features: operating currents, size - PowerPoint PPT Presentation
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HL-LHCCorrector Magnet
Design & ConstructionActivity Status
Giovanni Volpinion behalf of the LASA team
CERN, January 14 2014
Giovanni Volpini, CERN 14 January 2014 2
summary
• Magnet specs requirements: integrated field, radiation loads & material certificationoperating features: operating currents, size
• Cross section design 2D from 2- to 6- pole• Load lines, margins• Superconducting wire choice, insulation & impregnation scheme,
protection• Mechanical issues
assembly• Problems waiting for us just round the (3D) corner…
magnetic lengthcross-talk between magnetsfringe field (“harmonics” at the magnet ends)forces between magnets
magnet specs & operating features
NameOrientation
Order
Aperture
Int strenght at radius = 50 mm
Magnetic length
Operating
current
Wire diamet
er
Outer radius
(construction)
Stored energy
Inductance
TOTAL
[-] [mm] [Tm] [m] [A] [mm] [mm] [J] [H]
MCQSX S 2 150 1.00 0.789 300 0.7 230.0 30412.8 0.676
MCSX N/S 3 150 0.06 0.108 150 0.5 150.0 1200.5 0.107
MCOX N/S 4 150 0.04 0.108 150 0.5 150.0 654.2 0.058
MCDX N/S 5 150 0.03 0.122 150 0.5 150.0 588.7 0.052
MCTX N 6 150 0.09 0.456 150 0.5 150.0 2649.4 0.235
MCTSX S 6 150 0.015 0.076 150 0.5 150.0 441.6 0.039
Giovanni Volpini, CERN 14 January 2014 3
Giovanni Volpini, CERN 14 January 2014 4
Cross-sections
yoke
yoke
coil
coil
recooler pipe
Sextupole
Quadrupole
bore
bore
Giovanni Volpini, CERN 14 January 2014 5
2D cross sections: 4-pole
Yoke radius = 230 mm
Recooler bore D 50 mm @ r = 190 mm
Jeng (overall) ~ 300 A/mm²
Bpeak iron = 2.43 T
Bpeak coil = 2.82 T
Warning:no stray field
Giovanni Volpini, CERN 14 January 2014 6
2D cross sections: 6-pole
Yoke radius = 160 mm
Recooler bore D 50 mm @ r = 190 mm, so it’s outside the yoke
Jeng (overall) ~ 260 A/mm²
Bpeak iron = 3.7 T
Bpeak coil = 2.0 T
03.12.2013 p 140
Giovanni Volpini, CERN 14 January 2014 7
2D cross sections: 8- poleYoke radius = 160 mm
Recooler bore D 50 mm @ r = 190 mm, so it’s outside the yoke
Jeng (overall) ~ 260 A/mm²
8-poleBpeak iron = 2.5 TBpeak coil = 1.8 T
Giovanni Volpini, CERN 14 January 2014 8
2D cross sections: 10- 12- poleYoke radius = 160 mm
Recooler bore D 50 mm @ r = 190 mm, so it’s outside the yoke
Jeng (overall) ~ 260 A/mm²
12-poleBpeak iron = 2.8 TBpeak coil = 1.8 T
10-poleBpeak iron = 2.65 TBpeak coil = 1.8 T
Giovanni Volpini, CERN 14 January 2014 9
SC wires
Bruker-EAS NbTi for Fusion applicationFine filaments PF wiresWire type 2
Cu:NbTi ≈ 2.30Number of filaments 3282Filament diameter≈ 8 μm @ 0.73 mmTwo wire diameters: 0.5 and 0.7 mmS-glass insulation, An order for 8 km + 8 km will be issued in Jan 2014
Luvata PoriOK3900 Cu:NbTi ≈ 2.00Number of filaments 3900wire diameter 0.575 mm Filament diameter≈ 5.3 μmBare wireAn order for 20 km will be issued early in 2014
- Small wire (low operating current), but not too small (must be easy to handle, insulation should not reduce too much the Je);- High Cu content (again, low operating current, protection (4-pole));- From the shelf product (season sale?): small amount required (10’s of kg);- Small filament (not a strict requirement, but these magnets are designed to operate in the whole range 0-Imax;
Giovanni Volpini, CERN 14 January 2014 10
200 400 600 800C urrent A 1
2
3
4
5
6F lux dens ity T Quadrupole load line
B @ r=50mm
Design current = 300 A
Ic 350 A @ 5 T, 4.22 K
Tcs = 5.9 K
1.9 K
4.22 K
Bpeak on coil
Giovanni Volpini, CERN 14 January 2014 11
100 200 300 400C urrent A
1
2
3
4F lux dens ity T
6- and 12-pole load lines
Bpeak on coil
B @ r=50mm
Design current = 150 A
4.22 K
Ic 179 A @ 5 T, 4.22 KSextupole
Dodecapole
1.9 K
Sextupole
Dodecapole
Giovanni Volpini, CERN 14 January 2014 12
Field optimization
Geometrical harmonics are controlled by changing the pole profile from the ideal hyperbolic profile; no action has been taken to control saturation harmonics.Small effect in case we use non circular iron yoke profile.We fear that much larger harmonics will appear at the magnet ends when the 3D computations are made.
0 .5 1 .0 1 .5 2 .0
1 .0
0 .5
0 .5
1 .0
100 200 300 400 500 600C urre nt A
50
40
30
20
10
U n its
100 200 300 400C urre nt A
2
4
6
8
U n its
Design current = 150 A
Design current = 300 A
Quadrupole Sextupole
a6
a10
a14 a9
a15
a21
Giovanni Volpini, CERN 14 January 2014 13
Magnet protectionQuench protection is based on an external resistor dump. The maximum voltage Vmax is provisionally fixed at 100 V (6-pole to 12-pole) and 300 V (4-pole);
any interest to keep Vmax < 50 V? possible to raise Vmax > 300 V?
protection does not rely on quench heater; they could be considered for test purposes;
the peak temperatures are computed in two limiting case: vquench→ 0 (worst case) and vquench→∞ (limiting the quench to one coil only);
quench detection and switch operation time neglected;
conclusion: quench does not seem a critical point –not obvious, but likely-; a more detailed quench computation with proper propagation speed has to be performed when the design reaches its final stage.
n Iop[A] T[K] Rcoil [Ω] Rdump [Ω]
vquench ∞ 0
2 300 119.4 >300 7.48 >> 1.000
3 150 49.3 58.7 0.332 < 0.667
4 150 37.8 39.3 0.089 << 0.667
5 150 35.9 36.9 0.065 << 0.667
6 150 76.9 243.5 1.757 > 0.667
Giovanni Volpini, CERN 14 January 2014 14
Insulation & impregnation scheme Polyimide:
Neither European company is able to provide kapton insulated wire, at least for such small supplies;could not identify an external supplier for dip coating, but only tape coating;doubtful behaviour during impregnation w.r.t. fiberglass: is polyimide porous enough and does it stick well to the resin?
Fiberglass: one wire supplier will provide the wire already insulated with S-2 glass, with a 0.14 mm total (i.e. on diameter) thickness;discussions in progress with a specialized company to study the insulation procedure for the bare wire;
ImpregnationCTD-101K seems to be the most used and well known resin system. We understand that its radiation endurance properties are compliant with the design requirement. We are starting to develop the impregnation procedure with this resin.
Giovanni Volpini, CERN 14 January 2014 15
Assembly
The coils are not in contact with the pole. The spacer and the pole profile are tapered to match closely the coil to the pole, before tightening the screws of the wedge.
coil
pole
wedge
spacer
Giovanni Volpini, CERN 14 January 2014 16
3D design
Yoke laminations machined by laser cutfollowed by EDM (final accuracy 1/100 mm) on the relevant surfaces: poles, coil slots, alignment slots.
Assuming 5.8 mm thick iron; placing an order in parallel to CERN one?
Sestupole preliminary design
Giovanni Volpini, CERN 14 January 2014 17
460.00
320.00
190.00
R 25.00
5.00
15.00 R 160.00
R 230.00
interfaces & interferences
Alternative iron design for 6-to-12 pole, allowing better alignment and/or connection with the 4-pole and other magnets.Impact on field quality negligible.
4-pole iron radius
6-8-10-12-pole iron radius
recooler pipe
Mechanical & electrical connection between magnets and LHe vessel to be defined, along with room for bus-bars etc.
Iron radii used in the computations
18
Winding and impregnation tooling: first tests
Giovanni Volpini, CERN 14 January 2014
Giovanni Volpini, CERN 14 January 2014 19
open issues summary
Questions to be answered as soon as possible…
• operating currents;• outer iron diameter & shape;• radiation hardness compliance, insulation & impregnation;• field quality & fringe field; • mechanical & electrical connection between magnets and LHe
vessel to be defined, along with room for bus-bars etc.;
…and, not to be forgotten:
the MgB2 solution (playground)
other solutions (combined function magnet)?
Giovanni Volpini, CERN 14 January 2014 20
Next steps
DesignProblems waiting for us just round the (3D) corner…
magnetic lengthcross-talk between magnetsfringe field (“harmonics” at the magnet ends)forces between magnets (March 2014)
Residual magnetization at I=0 and impact on the harmonics
Cross check COMSOL results w/ Roxie (March 2014)
Mechanical design (May 2014)
Construction & testWind & impregnate a dummy coil (June 2014)Design the test cryostat
Giovanni Volpini, CERN 14 January 2014 21
End
(Episode I)
Acknowldgments
Paolo Fessia Remi Gauthier
Susana Izquierdo BermudezDavide Tommasini
…