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Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 2
Introduction
• The first TQ magnets, TQC01 and TQS01 and SQ-02 use– 0.7mm Modified Jelly-Roll strands “borrowed” from FNAL’s
inventory• 27-strand cable with 1.0 Deg keystone angle• Strand is of the 54/61 design with large effective filament
diameter ~ 70-80 m• Using “Nominal” heat treatment Jc > 2000 A/mm2 but
the strand has a low stability current Is• We now understand that Is in unstable strands is strongly
influenced by “dynamic” effects – Improve thermal environment Increase RRR of
stabilizing copper– Achieve this by preventing excessive reaction of Nb-
barrier – Optimize Reaction Time/Temp to increase the stability
current to be well above magnet operating current
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 3
Heat-Treat Optimization
Jc(12T-15T)
RRRBc2
HT-Temp 635C-695C
& TimeHigher Bc2 at
higher T
Strand Stability for large Deff
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 4
Ic and Is of virgin and of Strands Extracted from LARP Proto-type Cables
Wire ID FIELD, T *12 11HT parameters Temp TIME Ic(A) Ic(A) Is(A) RRR
ORE-205-virgin 210/48+400/48+665/72 665 72 439 533 522 12913R-A-Extr. 210/48+400/48+665/72 665 72 435 523 419 13910R-A-Extr. 210/48+400/48+665/72 665 72 443 532 412 13ORE-206-C-Virgin 210/48+400/48+665/72 665 72 442 531 506 12
ORE-206-C-Virgin 210/48+400/48+650/72 650 72 417 513 887 98913R-A-Extr. 210/48+400/48+650/72 650 72 404 496 637 73910R-A-Extr. 210/48+400/48+650/72 650 72 436 531 837 84
913R-A-Extr. 210/48+400/48+635/72 635 72 389 480 887 202ORE-205-virgin 210/48+400/48+635/72 635 72 389 478 1200 302
ORE-205-virgin 210/48+400/48+650/48 650 48 418 511 1200 247913R-A-Extr. 210/48+400/48+650/48 650 48 389 477 1100 189910R-A-Extr. 210/48+400/48+650/48 650 48 397 487 1200 218
ORE-205-virgin 210/48+400/48+635/48 635 48 373 461 1200 310913R-B-Extr. 210/48+400/48+635/48 635 48 369 457 1200 275
* 12T is an extrapolation using the Summers' formulation
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 5
Commercial sources of high Jc Nb3Sn
• With the exception of ShapeMetal Innovation, Netherlands, (SMI), which uses Powder-in-tube technology (PIT) and has delivered strand to FNAL in the past, there is only one reliable source of high-Jc strand in the US.
• Oxford Superconducting Technology (OST)– MJR Conductor has been phased out– Present technique is RRP (Rod-Restack Process)
• Uses a distributed barrier approach• Jc (12T) ~ 3000 A/mm2
• Effective Filament Diameter Deff~ Sub-element Diameter
– Deff scales inversely with increasing number of Sub-elements
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 6
RRP strand
• Long-lead item ~ 6-9 months after placing order• SC vendor planning ~12-13 months• Under the direction of the Conductor Development
Program, OST has developed strands with increasing number of sub-elements to reduce Deff
Billet 7054 54/61
Billet 7904 126/127
Billet 8079 90/91
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 7
RRP Strand for LARP
– OST has the most experience in fabricating strands of 54/61-stack design. This is considered a “production” wire used in the NMR business
– Very limited experience with the 91 or the 127 stack design. These billets are presently considered by OST to be R&D billets.
• For FY06 LARP would like to use strands with the 84/91-stack design
• Why? Why not use the “production” 54/61 strand ?– Stability will improve with decreasing sub-element
diameter• Question is how to move from R&D to “production” at OST
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 8
Nb3Sn Strand Specification84/91 Design
Process Ternary RRP Nb3SnDiameter, mm 0.7 ± .0025
Jc(12 T), A/mm2
≥ 2400
Deff, µm < 60
IS, A > 1200 A
Cu-fraction, % 50 ± 2RRR ≥ 100RH twist, mm 15 ± 1Minimum Piece length, m 350High temperature HT duration, h ≥ 48
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 9
Nb3Sn Strand Specification54/61 Design
Process Ternary RRP Nb3SnDiameter, mm 0.7 ± .0025
Jc(12 T), A/mm2
≥ 2400
Deff, µm < 70
IS, A > 1200 A
Cu-fraction, % 50 ± 2RRR ≥ 100RH twist, mm 15 ± 1Minimum Piece length, m 350High temperature HT duration, h ≥ 48
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 10
Conductor Development Program
• CDP has been the main driver in OST’s high-Jc strand R&D. – It continues to fund this development in FY06
– Main Goals reduce Deff, billet “scale-up”, (NbTi)3Sn
• LARP can take advantage of the strand that is in the CDP inventory to conduct strand characterization for use in TQ-type cable
• LARP can also “borrow” from the CDP inventory
• At present OST is fabricating strand for CDP that is similar to strand being considered for LARP purchase
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 11
CDP-R&D Inventory
Compiled with D.R Dietderich
Yield of billet 8502 is ~ 50% due to wire breakage
Billet 8521 is in process, yield not known
Billet Type StackRod
Composition
Diameter
(mm)
non-Cu (%)
Weight (kg)
Length (m)
CDP PurChase
Delivery Date
8079 RRP 90/91 Nb-(Ti) 0.7 59 30 6203 R&D at LBNL
8220 RRP 54/61 Nb-Ta 0.7 53.8 36 10776 Y at LBNL
xxxx RRP 54/61 Nb-Ta 0.7 50 35 Y 11/30/2005xxxx RRP 84/91 Nb-Ta 0.7 50 35 Y 11/30/2005xxxx RRP 84/91 Nb-Ta 0.7 50 90 Y 3/31/20068502 RRP 84/91 Nb-Ta 0.7 50 15 R&D 9/30/20058521 RRP 108/127 Nb-Ta 0.7 50 30 R&D 9/30/20058466 RRP 198/217 Nb-Ta 0.7 50 NM R&D 9/30/2005
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 12
Comments• 30 kg can be fabricated into 5 UL’s each 65m long. Each UL is for a TQ-
coil
• With the exception of billet 8079, all the strand in CDP inventory is the high Sn-content capable of a Jc of 3000 A/mm2. The most recent billet 8220 (54/61-design) has this Jc and a RRR ~ 200. With this RRR the stability current is ~ 1000-1100 A.
• Most of the RRP strand at 0.7mm have yet to be cabled as a TQ-cable with 1.0 deg keystone. LBL has recently made a short (17m) trial piece of 27-strand TQ cable using strand from 8220. This is being evaluated for Ic, Is and RRR.
• A short length ~ 4m of cable has also been fabricated using strand from 8079 (90/91-design), this too is under evaluation. Strands from this billet show stability currents > 1200A.
• For strands with either the 61, 91 or 127 stack, the key parameter that ensures a high stability current is the RRR of the copper stabilizer.
– Provided the copper remains clean, strand stability increases as the stack number is increased i.e. sub-element size is decreased
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 13
Recent OST Billets
WireID HT_Temp HT_Time Jc(12T) Ic(12T) Ic(11T) Is RRR54/61-DesignRRP-8220-4 665 50 3022 622 750 1125 171RRP-8220-4 665 50 3208 660 796 1012 190RRP-8220-4 665 50 3080 634 761 1125 178RRP-8220-4 680 48 3169 652 773 111RRP-8220-4 650 48 2923 602 731 1075RRP-8220-4 650 96 3108 640 773 112590/91-DesignRRP-8079-7 635 48 2473 561 676 >1200 357RRP-8079-7 635 36 2325 528 638 >1200 344RRP-8079-7 635 48 2457 558 670 >1200 356126/127-DesignRRP-7904 650 72 2257 513 633 300 4RRP-7904 635 72 2041 463 578 525 8.8
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 14
Target Program
Sept 26, 2005 Type Strand Length Gradient Peak Bore FY05 FY06 FY07 FY08 FY09
process [m] [T/m] Field [T] [mm]
MODEL MAGNETS
Technology Quad (TQ) cos(2q) MJR 1 > 200 90 2*
RRP 1* 2
Long Quad (LQ) cos(2q) RRP 4 > 200 90 1 1
High Gradient Quad (HQ) cos(2q) RRP? 1 > 250 90 1 1
SUPPORTING R&D
Practice Coil (PC) cos(2q) RRP 4 N/A 90 2
Sub-scale Quad (SQ) block MJR 0.3 ~100 110 1*
RRP 1* 1* 1
Short Racetrack (SR) block RRP 0.3 10-12 N/A 1 1* 1
Long Racetrack (LR) block RRP 4 10-12 N/A 1 1
* In addition to building new coils there will be several revised configuration tests using existing coilsRRP: Rod Restack Process (84/91)MJR: Modified Jelly Roll
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 15
Total Conductor Estimate
Series# of Magnets Kg/Magnet Total
TQ 5 35 175
LQ 2 165 330
HQ 2 88 176
Series# of Magnets Kg/Magnet Total
PC 2 40 80
SQ 4 10 40
SR 3 5 15
LR 2 60 120
Total
Total 936 kg
Plan for 1100 kg
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 16
Procurement Plan
1100 kg
FY06300 kg
FY07400 kg
FY08400 kg
85 kgFNAL
95 kg3/31/06
60 kg7/31/06
60 kg10/31/06
Plan A54/61
Plan B84/91
Low-Risk
Low Risk
Higher Risk
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 17
Procurement Strategy
• CDP has two billets on order which uses the same sub-element with the potential for Jc(12T) ~ 3000 A/mm2
– One uses 54/61 design– The other 84/91 design – Delivery 11/31/05
• CDP is also placing an order for 90 kg for high Jc wire using the 84/91 design Delivery 3/31/06
• LARP will place an initial order for 95 kg (this is the yield from one sub-element extrusion billet)– 54/61 design Delivery 3/31/06
This allows for material to be in the pipeline that we are certain to have in hand for the magnets being fabricated in FY06. If the 84/91 billets for CDP are successful then LARP could “swap” that with the 54/61 wire delivered under its order
Collaboration Mtg, St Charles, IL 10/5-6, 2005
A. Ghosh 18
Summary
• Present Status– Draft specification sent to OST– Wire from Billet 8502 (84/91) arriving LBL 10/10/30– This wire needs to be characterized for Ic, Is and RRR– Cable using billet 8220 (54/61) under investigation
• LARP order needs to be placed soon