HL-LHCCorrector Magnet3D design status

Giovanni Volpinion behalf of the LASA team

CERN, February 25, 2014

Giovanni Volpini, CERN 25 February 2014 2

Specification done, design in progress

First tests, first experiences…

To start when a 3D em “stable” design is issued

To be done

So far, looks OK

Work status

Magnets DesignProblems waiting for us just round the (3D) corner…

magnetic lengthcross-talk between magnetsfringe field (“harmonics” at the magnet ends)forces between magnets

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

Being addressed

Giovanni Volpini, CERN 25 February 2014 3

Sextupole cross-section

yoke

coil

Sextupolebore

Giovanni Volpini, CERN 25 February 2014 4

3D design: geometry

rectangular, race track, coils;iron yoke extruded;option for a stray flux return yoke investigated in the COMSOL model

COMSOL

Roxie

with flux return

without flux return

Giovanni Volpini, CERN 25 February 2014 5

Computations performed

Using the two codes to cross-check & validate the results

Linear iron (µr = 4000) to validate a model & cross-check results

“Roxie”- like saturating iron with filling factor 0.985

Six cases {40 mm, 50 mm, 60 mm} x {with RY, without RY (Air)}For each the following current have been considered{20 A, 50 A, 100 A, 150 A, 200 A, 300 A, 400 A}

For each case, Longitudinal & Integrated A3/B3, integrated harmonics, peak field on conductor

Giovanni Volpini, CERN 25 February 2014 6

COMSOL vs Roxie

Use two codes to cross-check & validate the results:• COMSOL + Mathematica for harmonic analysis;• Roxie

2D results: agreement within few parts/104 on fields; few % on relevant harmonics. Satisfactory for our purposes.WARNING: use of LSOLV in Roxie option leads to inaccurate results, with a discrepancy w.r.t. COMSOL as large as 3% on fields.

3D results: agreement within ~1% on fields; 10% on relevant harmonics. Acceptable but not exciting.

Giovanni Volpini, CERN 25 February 2014 7

Giovanni Volpini, CERN 25 February 2014 8

0 .0 0 0 .0 5 0 .1 0 0 .1 5 0 .2 0Inte gra te d B 3 T mA

A

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R Y

R Y

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1 2 3 4B p e a k o n c o ils T

1 0 0 0 0

2 0 0 0 0

3 0 0 0 0

4 0 0 0 0

5 0 0 0 0

6 0 0 0 0

M a gne to mo tive fo rc e A turns Operating point & length, I

Design integrated strength 60 mT m

Desig

n o

pera

tin

g c

urr

en

t ra

tio v

s.

s.s

. lim

it (

40

%)

… vs integrated B3

…vs peak field on coils

We compute the Ic at the peak field at s.s. limit. Dividing the magnetomotive force at s.s. limit by Ic, we get the no. of turns required.Dividing the operating magnetomotive force by the no. turns, we get the operating current.

Giovanni Volpini, CERN 25 February 2014 9

WITHOUT R.Y. WITH R.Y.

Iron length [mm] 40 50 60 40 50 60

Operating magnetomot. force

[A turns] 31104 22312 18290 37919 26056 20235

Bpeak at s.s. limit [T] 4.67 3.69 3.25 5.71 4.83 3.52

Wire Ic [A] 338.4 411.1 451.4 276.5 327.6 425.4

Operating current [A] 135.4 164.5 180.6 110.6 131 170

No. Turns required [-] 228 136 101 343 199 119

Operating point & length, II

2D design was made with 166 turns x 150 A, the operating point was around the 40% on the load line.

Giovanni Volpini, CERN 25 February 2014 1010 1005020 3015 15070

z axis mm10 4

0.001

0.01

0.1

1A 3 r 50 mm T A 3 component integrated stregth 0.06 Tm

B3/A3 component inside and outside

Iron length(w.o. flux return, if present)

nominal “magnetic ½length”

(60.5 mm)

nominal spacing between magnets (100 mm)

∫−∞

∞

|𝐵3|𝑑𝑧=60mT ∙m

with flux return

without flux return

Giovanni Volpini, CERN 25 February 2014 11

a9 component

WITHOUT R.Y. WITH R.Y.

Iron length [mm] 40 50 60 40 50 60

I = 20 A26.0 20.4 15.8 6.1 3.9 2.6

I = 150 A26.8 21.8 17.7 4.3 3.6 3.1

In units 10-4

Giovanni Volpini, CERN 25 February 2014 12

summary

For the sextupole, the overall 3D e.m. design seems compatible with the space constraints;

Flux return at the magnet ends : for a given magnetomotive force and iron length, is less effectivereduces the stray fieldreduces the integrated harmonicsso it is probably OK: any drawback?hole shape

Harmonics content not critical, numbers appear acceptable, Flux Return is also effective in reducing unwanted components.

Giovanni Volpini, CERN 25 February 2014 13

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 25 February 2014 14

Exiting from Flatland may be a though experience…

The End

Giovanni Volpini, CERN 25 February 2014 15

Other slides

Giovanni Volpini, CERN 25 February 2014 16

WITHOUT R.Y. WITH R.Y.

Iron length [mm] 40 50 60 40 50 60

Operating magnetomot. force

[A turns] 31104 22312 18290 26056 20235

Bpeak at s.s. limit [T] 3.92 3.08 2.76 3.50 2.98

Wire Ic [A] 391.8 469.2 504.0 427.1 479.8

Operating current [A] 196 235 252 214 240

No. Turns required [-] 160 95 73 122 84

Operating point @ 50% of s.s.

2D design was made with 166 turns x 150 A, it was around the 40% on the load line.

Giovanni Volpini, CERN 25 February 2014 17

Infinite elements

10 1005020 3015 15070z axis mm10 4

0.001

0.01

0.1

1B r 50 mm T F ield main component integrated stregth 0.06 Tm

Iron half length 50 mmWith flux return

With (red)Without (purple) infinite elements

ImpactIntegrated strength < 0.1%Main component < 0.01 %Int b9 < 2 units

Giovanni Volpini, CERN 25 February 2014 18

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 25 February 2014

19

Giovanni Volpini, CERN 25 February 2014 20

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 25 February 2014 21

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