D.R. Dietderich Frascati, Italy Nov. 14-16, 2012 RRP-NbSn Conductor for the LHC Upgrade Magnets...

D.R. Dietderich Frascati, Italy Nov. 14-16, 2012

RRP-Nb3Sn Conductor for the LHC Upgrade Magnets

A. K. Ghosh and D.R. Dietderich, A. Godeke

Hi-Lumi LARP collaboration meetingFrascati, Italy Nov 14-16, 2012

1


Outline

• Introduction• RRP® 108/127 Strand

– OST strand production

• Ti-Ternary Strand• RRP® strands with smaller

filaments– 169 and 217 re-stack

• Summary


Introduction• The LARP program (LHC Accelerator Research

Program) goal is the development of high gradient large aperture quadrupoles

• It started with MJR 54/61 conductor from Oxford Superconducting Technology (OST), and transitioned to RRP® 54/61 conductor

• The RRP 54/61 strand is a “production” wire with predictable high Jc at 12 T and 15 T – RRR > 200 – Long piece lengths

• Only drawback: ds, the sub-element size, is large– 75 mm for 0.8 mm wire

• Transitioned to 108/127 to reduce filament diameter


Ta-Ternary RRP® 108/127 Wire

• Oxford Superconducting Technology has delivered ~ 190 km of wire to the LARP program for the LQ and HQ magnets ~ 25 billets

4

• Strand Diameter, mm0.778

• Jc(12 T) at 4.2 K, A/mm2 > 2650• Jc(15 T) at 4.2 K, A/mm2 ~ 1400• ds, µm (nominal) 50• Cu-fraction, %

53 ± 3• Cu/non-Cu

1.13Wire Reaction schedule

210 oC/72h + 400 oC/48h + 665 oC/50h


E-2004 type high Jc RRP

Sampling of billets produced 2002-2007

non-

Cu

Jc

(4.2

K),

A/m

m2

0

500

1000

1500

2000

2500

3000

3500

12 T Jc 15 T Jc

12 T

15 T

< Jc >= 2960

< Jc >= 1550

RRP 54/61: 2002-2007 RRP 108/127: 2008-2012

Jc of 108/127 are somewhat lower than for 54/61

500

1000

1500

2000

2500

3000

3500

RRP-

1042

8 BE

RRP-

1042

9 BE

RRP-

1043

3 BE

RRP-

1200

8 BE

RRP-

1231

9 BE

RRP-

1239

1-3

BERR

P-12

520

BERR

P-12

878-

1 BE

RRP-

1287

8-2

BERR

P-12

879

BERR

P-12

885

BERR

P-13

090

BERR

P-13

091

BERR

P-13

154

BERR

P-13

211

BERR

P-13

376

BERR

P-13

377

BERR

P-13

596

BERR

P-13

618

BERR

P-13

658

BERR

P-13

659

BERR

P-13

699

BERR

P-13

700

BERR

P-13

709

BERR

P-13

710

BERR

P-13

711

BERR

P-13

916

BERR

P-13

917

BERR

P-13

918

BERR

P-13

965

BERR

P-13

980

BERR

P-14

007

BERR

P-14

070

BERR

P-14

144

BERR

P-14

205

BERR

P-14

206

BERR

P-14

243

BERR

P-14

244

BERR

P-14

394

BERR

P-14

395

BERR

P-14

396

BERR

P-14

397

BE

J c(non

-Cu)

, A/m

m2 <Jc (12T)> = 2865 A/mm2

s =112 A/mm2

Jc (12T)Specs> 2650 A/mm2

<Jc (15T)> = 1410 A/mm2

s =90 A/mm2

Jc of 108/127 wire – 42 billets

Courtesy of Jeff Parrell (OST)


RRR of 108/127 wire

Specs. > 60

0

50

100

150

200

250

RRP-

1042

8 BE

RRP-

1042

9 BE

RRP-

1043

3 BE

RRP-

1200

8 BE

RRP-

1231

9 BE

RRP-

1239

1-3 B

ERR

P-12

520 B

ERR

P-12

878-

1 BE

RRP-

1287

9 BE

RRP-

1288

5 BE

RRP-

1309

0 BE

RRP-

1309

1 BE

RRP-

1315

4 BE

RRP-

1321

1 BE

RRP-

1337

6 BE

RRP-

1337

7 BE

RRP-

1359

6 BE

RRP-

1361

8 BE

RRP-

1365

8 BE

RRP-

1365

9 BE

RRP-

1369

9 BE

RRP-

1370

0 BE

RRP-

1370

9 BE

RRP-

1371

0 BE

RRP-

1371

1 BE

RRP-

1391

6 BE

RRP-

1391

7 BE

RRP-

1391

8 BE

RRP-

1396

5 BE

RRP-

1398

0 BE

RRP-

1400

7 BE

RRP-

1407

0 BE

RRP-

1414

4 BE

RRP-

1420

5 BE

RRP-

1420

6 BE

RRP-

1424

3 BE

RRP-

1424

4 BE

RRP-

1439

4 BE

RRP-

1439

5 BE

RRP-

1439

6 BE

RRP-

1439

7 BE

RRR

<RRR> = 101s = 45

Sampling of billets produced 2002-2007

RR

R

10

100

RRP 54/61: 2002-2007

RRP 108/127: 2008-2012

• Considerable variation in RRR• Can be increased by 650 oC/48h reaction

5% loss in Jc

• Reducing Sn content by 5% Recent billets show marked increase in RRR


RRR of 108/127 billets with reduced Sn-content

7

Billet Jc(12T) Jc(15T) RRRRRP-14752 FE/BE 2864/2914 1524/1535 168/242RRP-14753 FE/BE 2905/3015 1509/1594 245/213RRP-14793 FE/BE 2914/2947 1503/1541 114/80RRP-14794 FE/BE 2956/2933 1525/1531 66/57

No difference in Jc

Significant Improvement in RRR

Reduced

Normal


Ti-Ternary strand

• So far all LARP magnets have been made using Ta -Ternary Nb3Sn wire (Nb-7.5 wt% Ta ) (Nb- 4 a% Ta)

• Ti-doping also increases Hc2 of the binary alloy

Ti and Ta alloying raises Hc2 by ~ 4 T at 4 K

M. Suenaga, IEEE Trans. on Magnetics, 21,1985


Ti –Ternary RRP Strand - higher HK at lower reaction temp.

21

22

23

24

25

26

27

28

620 630 640 650 660 670 680 690 700

Reaction Temperature, oC

HK,

T

(Nb-Ti)3Sn

(Nb-Ta)3Sn

Ghosh, Cooley, OST collaborators, ASC2006

96 h

144 h

Kra

me

r fie

ld e

xtra

pola

tion

from

da

ta a

t 7 -

11.5

T

0.7 mm

At 650 oC/48h , Ti-Ternary has higher Jc(15T) than Ta-Ternary

48 h48 h


Ti-Ternary vs. Ta-Ternary: Strain tolerance

350

400

450

500

550

600

650

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Sample loadedSample unloaded

Crit

ical

Cur

rent

, I c (

A)

Applied Strain, (%)

Ec = 0.1 V/cm

T = 4 KB = 12 T

irr

~ 0.62 %

max

~ 0.37 %

A'B'C' G'H' I'J'

CDE F GHI

J

A B

D'E'F'

KL

MN

O

P

Q

R

S

K'L'M'

N'O'

P'

Q'

R'

S'

(b)

Ti-doped RRP Nb3Sn wire

irr,0

= 0.25 %

250

300

350

400

450

500

550

600

0 0.1 0.2 0.3 0.4 0.5 0.6


Crit

ical

Cur

rent

, I c (

A)

Applied Strain, (%)

Ec = 0.1 V/cm

T = 4 KB = 12 T

irr

~ 0.37 %max

~ 0.33 %

A' B'C'

G'

H'

I'

J'

CD

EF

G

H

I

J

A B

D'E'F'

(a)

Ta-doped RRP Nb3Sn wire

irr,0

= 0.04 %

350

400

450

500

550

600

650

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7


Crit

ical

Cur

rent

, I c (

A)

Applied Strain, (%)

Ec = 0.1 V/cm

T = 4 KB = 12 T

irr

~ 0.62 %

max

~ 0.37 %

A'B'C' G'H' I'J'

CDE F GHI

J

A B

D'E'F'

KL

MN

O

P

Q

R

S

K'L'M'

N'O'

P'

Q'

R'

S'

(b)

Ti-doped RRP Nb3Sn wire

irr,0

= 0.25 %

250

300

350

400

450

500

550

600

0 0.1 0.2 0.3 0.4 0.5 0.6


Crit

ical

Cur

rent

, I c (

A)

Applied Strain, (%)

Ec = 0.1 V/cm

T = 4 KB = 12 T

irr

~ 0.37 %max

~ 0.33 %

A' B'C'

G'

H'

I'

J'

CD

EF

G

H

I

J

A B

D'E'F'

(a)

Ta-doped RRP Nb3Sn wire

irr,0

= 0.04 %

N. Cheggour, et al., Supercond. Sci. and Tech., 20, (2010)

Ti-doped Nb3Sn wire more strain tolerant than Ta-doped

Confirmed for RRP® designs 54/61, 90/91, 108/127, 198/217

Data of N. Cheggour


RRP® Ti-Ternary vs. Ta-Ternary

Advantages of Ti-Ternary

Does not require Nb-7.5wt% Ta alloy rodsTi introduced by Nb – 47 wt.% Ti rods

Ti content can be tweaked easily to maximize Hc2

Ti accelerates Nb3Sn reaction At 650 oC/48h , Ti-Ternary has higher

Jc(15T) than Ta-Ternary Higher strain tolerance

i.e. higher irreversible strain limitRecently OST delivered 112 kg of wire 108/127Jc (12/15 T): ~ 2900/ 1530 A/mm2


RRP® strands with smaller filaments

– Smaller sub-elements can minimize flux jumps and improve stability.

– Filament Magnetization decreases

Smaller Filament Size

Courtesy of Jeff Parrell (OST)


HEP- Conductor Development Program Development of 192/217 Design• 192/217 re-stack of 3000 A/mm2 class sub-elements (high Nb and Sn-content design used for 54/61 and 108/127) could not be processed to 0.8 mm

• 2400 A/mm2 class (lower Nb and Sn-content) processed to 0.8 mm in two long pieces• Ti-Ternary• For optimized Jc , RRR very low ~ 8. Very difficult to maintain high-Jc and RRR > 50 for smaller filaments


192/217 Re-stack Development

• To increase RRR new sub-element design

Increase starting Nb filament diameterControl roundness of Nb mono-rods Increase spacing between Nb filaments Increase barrier thickness

• New 2700 A/mm2 class conductor being fabricated

• First results from OST for wire fabricated with 30% thicker barrier -- 0.778 mm diameter

• 650C/ 50 h • Jc (12T) = 2590 A/mm2

• Jc (15T) = 1350 A/mm2

• RRR 118-129


CDP – New RRP 192/217 (Ti-doped)

0.778 mm

1.00 mm

0.85 mm

0.85 mm

D.R. Dietderich Frascati, Italy Nov. 14-16, 2012 16

Another Option– 169 re-stack

•10 km delivered to CERNTi-Ternary, 1.0 mmd ~ 57 mm Jc(12T) ~ 3050 A/mm2

Jc(15T) ~ 1680 A/mm2

RRR 140 – 200•1.0 mm wire when drawn down to 0.80

mm shows very good properties d ~ 46 mm Jc(12T) ~ 3130 A/mm2 Jc(15T) ~ 1630 A/mm2 RRR ~ 100

132/169


Sub-element (Filament) diameter, mm

35 kg Billet

Cu/Non-Cu=1.2 , 45.5% SC

R=Cu/Non-Cu=1.2 , 45.5% SC, 54.5 % CuStrand

Design 54/61 84/91 108/127 150/169 198/217 252/271 312/331 # of Sub-elements

D w , mm 54 84 108 150 198 252 312

1.0 92 74 65 55 48 42 380.85 78 63 55 47 41 36 32

0.778 71 57 50 43 37 33 300.7 64 52 45 39 34 30 27

Presently, sub-element rod sizes are very small for assembly of 217. Larger diameter re-stack billets will make it easier to control production of 217, and enable re-stacks with higher number of sub-elements.

RN

Dd ws

1


Summary

• Present Status of RRP wire

108/127 design has good Jc properties RRR being controlled by reducing Sn-content without loss

of Jc 132/169 or 150/169 is an emerging option for wire

diameter > 0.80 mm or 0.85 mm Ti- ternary allows lower reaction temperature for

equivalent Jc and higher HK than the Ta-ternary

Higher Jc at 15 T 217 Re-stack strand with thicker barrier is being

developed scale-up to 60 kg will further enable this re-stack

design

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End of Presentation

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D.R. Dietderich Frascati, Italy Nov. 14-16, 2012 RRP-NbSn Conductor for the LHC Upgrade Magnets...

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