Harold G. KirkBrookhaven National Laboratory

High-Field Solenoids for a MC Final Cooling System

AAC 2012

Austin, Texas June 11-15, 2012

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Muon Collider Parameters

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The MC Cooling Scenario

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Proposed Final Cooling Lattice

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HTS R&D at BNLR. Gupta, P. Joshi, H. Kirk, R. Palmer, W. Sampson, Y.

Shiroyanagi and P. Wanderer Brookhaven National Laboratory

D. Cline, A. Garren, J. Kolonko, R. Scanlan, B. Weggel Particle Beam Lasers, Inc

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Two Solenoids are being built and tested

Solenoid #1(Mid-sert)ID = 10cmOD=17cm24 Pancakes

Solenoid #2(Insert)ID = 2.5cmOD=9.1cm14 Pancakes

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YBCOHigh Temperature Superconductor (HTS)

The HTS Conductor• 2G Superpower YBCO tape • 4 mm wide• 100μm thick• 1μm YBCO (Yttrium Barium Copper Oxide) layer

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YBCO measurements at National High Magnetic Field Lab (NHMFL) in Florida

YBCO Tape: Angular Dependence

The critical current of YBCO is very different between background fields perpendicular and fields parallel

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10 cm ID 2G Coils for Mid-sert

Each coil has ~240 turns and uses 100 meter tape (maximum one splice)

100 mm

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Test Results of 24 Coils at 77oK

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 240

10

20

30

40

50

60

Coil I.D.

Ic (A

)Proof That A Large Number of 2G HTS Coils Can be Built and Tested without

Degradation

Individual tests for each col

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Test of Half Mid-sert in LN2

(12 pancakes)

Overall performance is not limited by coils in the ends (where field perpendicular is largest). It is limited by 4th coil of the total 12 (i.e. one near the middle).

0

1000

2000

3000

4000

5000

6000

7000

8000

0 5 10 15 20 25

Volta

ge (m

icro

-vol

ts)

Current

@77 K coil 1

coil 2

coil 3

coil 4

coil 5

coil 6

coil 7

coil 8

coil 9

coil 10

coil 11

coil 120

1000

2000

3000

4000

5000

6000

7000

8000

0 10 20 30 40Vo

ltage

(mic

ro-v

olts

)Current

@67 K coil 1

coil 2

coil 3

coil 4

coil 5

coil 6

coil 7

coil 8

coil 9

coil 10

coil 11

coil 12

Coil voltages in individual coil as a function of current Coil numbers are counted from one end to another end

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Test Results at 4.2oKMeasured Critical Current As a function of Temperature

This is the first test of large aperture, high field 2G magnet and also one that uses over 1 km (1.2 km) wire

0255075

100125150175200225250275300

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Curr

ent (

A)

Temp(K)

Peak Field on Coil at 250 A : ~9.2 T

Coil operated with margin at 250 A

PBL/BNL 100 mm HTS Solenoid Test for Muon Collider 250 A ==> 9.2 T on coil5 T on Axis

Corresponds to 10T for full mid-sert

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Insert Solenoid Construction

• ID = 25 mm, OD = 91 mm• 4 mm wide 0.1 mm thick• Co-wound ~270 turns

with 4 mm, 0.025 mm thick stainless steel tape.

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7 double pancakes at 77oK

0

0.5

1

1.5

2

2.5

3

3.5

4

0 5 10 15 20 25 30 35

Volta

ge (m

V)

Current (A)

#7

0-50

50-100

100-150

150-200

200-250

250-266

7 double pancakes were built and individually tested at 77o K. Voltage taps were attached every 50 turns.

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Pre-test @67oK – 77oK

0 5 10 15 200.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0 14 Coil Voltages @77K

L1 L2 L3 L4

L5 L6 L7 L8

L9 L10 L11 L12

L13 L14

current (A)

Volta

ge (m

V)

Coil #11, #5 and #6 became resistive firstThese coils are near the middle of the solenoid not the at the edges

20 30 400.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.614 Coil Voltages @67 K

L1 L2 L3 L4

L5 L6 L8 L10

L11 L12 L13 L14

current (A)Vo

ltage

(mV)

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Summary of Test Results in LN2

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Test at 4.2o K

The critical current of this solenoid was only 16 A at 77o K, however , current reached 285 A at 4.2oK. At this current, the central field was over 15 T and the peak field on the conductor was over 16 T.

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In LHe In LN2

gas He

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Future PlansStep 1—Test together the full mid-sert and insert.

220A will yield 22T.Step 2—Test the mid-ser/insert combination within

the 20cm bore, 20T resistive magnet at NHMFL in Tallahassee.

Step 3—Depending on approval of an SBIR Phase II proposal, build a 13-15T Nb3Sn outsert coil with the goal of achieving 35T with an all superconducting solenoid.

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The Local Field Components

Field Parallel (~22 T) Field Perpendicular (~6 T)

Inner and outer coils together at design field

In computing short sample limits, both local fields and angles need to be considered.

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Future Task #2 20+ T magnet in ~20 T field for a ~40 T Test

• Utilize the 20cm bore, 20 T field from a resistive solenoid at NHMFL.

• Install support structures to deal with large hoop stresses • Update quench protection to take care of fault conditions

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Toward n all Superconducting 35T Solenoid

• Collaboration between Particle Beam Lasers, Inc. (PBL) and Brookhaven National Laboratory.

• An insert using YBCO HTS has reached a 15T axial field at 4.2oK.

• A full length mid-sert delivering a 10T axial field

• The mid-sert and insert together can deliver 22T

• An outsert using Nb3Sn capable of 13-15T is proposed.

outsert midsert

insert

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SUMMARY

Final cooling scenario for a Muon Collider requires 30-40T solnoids

An YBCO based HTS solenoid with an ID of 2.5cm has achieved and axial field of 15T

An YBCO based HTS solenoid with an ID of 10cm capable of 10T axial field is being tested

A Nb3Sn based solinoid with an ID of 20cm, capable of delivering >13T is proposed

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Backup Slides