HL-LHC Corrector Magnet Design & Construction Activity Status Giovanni Volpini on behalf of the LASA team CERN, January 14 2014

HL-LHCCorrector Magnet

Design & ConstructionActivity Status

Giovanni Volpinion behalf of the LASA team

CERN, January 14 2014

https://espace.cern.ch/HiLumi/Logo%20%20Pictures/HiLumi-large-1615px.jpg

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



Cross-sections

yoke

yoke

coil

coil

recooler pipe

Sextupole

Quadrupole

bore

bore


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


2D cross sections: 6-pole

Yoke radius = 160 mm

Recooler bore D 50 mm @ r = 190 mm, so it’s outside the yoke


Bpeak iron = 3.7 T

Bpeak coil = 2.0 T

03.12.2013 p 140


2D cross sections: 8- poleYoke radius = 160 mm



8-poleBpeak iron = 2.5 TBpeak coil = 1.8 T


2D cross sections: 10- 12- poleYoke radius = 160 mm






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;


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


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


4.22 K

Ic 179 A @ 5 T, 4.22 KSextupole

Dodecapole

1.9 K

Sextupole

Dodecapole


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



Quadrupole Sextupole

a6

a10

a14 a9

a15

a21


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


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.


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


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


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


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)?


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


End

(Episode I)

Acknowldgments

Paolo Fessia Remi Gauthier

Susana Izquierdo BermudezDavide Tommasini

…

Documents

HL-LHC Corrector Magnet Design & Construction Activity Status Giovanni Volpini on behalf of the LASA team CERN, January 14 2014