LARP Strand: Status of 108/127 : Past and Present Manufacture and Performance

1. BNL -FNAL - LBNL - SLAC LARP Strand: Status of 108/127 : Past and Present Manufacture and Performance • HiLumi-LHC/LARP Conductor and Cable Internal Review Oct 16-17, 2013By VideoArup K. Ghosh (BNL)

2. Outline • Introduction • Production History of 108/127 strand • Performance of 108/127 • Ta-Ternary • Ti-Ternary • Summary - Lessons Learned

3. Introduction • 108/127, 0.7 mm RRP® wire from Oxford Superconducting Technology first delivery of 90 kg in Feb-2008 under CDP contract • Used in TQS03 – a very successful 90 mm magnet • 2009-2012 substantial wire produced at 0.7 mm for LQ and 0.8 (0.778 mm) for HQ • Ta-Ternary : (Nb – 7.5 wt.% Ta)3Sn • 1300 Kg produced for LARP • 108/127 Ti-Ternary : CDP development 2009 • First delivery of 3 billets at 0.8 mm (using CDP funds)in Mar-2011 used for HQ-C18, C21 and a LHC coil • Good piece length • RRR in the range of 60-70 for HT of 665°C/50h • 410 Kg of Ti-Ternary wire delivered Sep’12 through Jan’13 • Introduced design change: 5% lower Sn content

4. OST production of 108/127 for LARP Production in parallel with ITER wire Note: In this time frame the yield of 54/61 declined 10% Ti-ternary piece-length better than Ta-Ternary

5. Performance Highlights of Ta-108/127 • OST qualified wires using the following HT schedule • 210°C/48h + 400°C/48h + 665°C/50h • Overall, a very large fraction of the billets surpassed the Jcminimum of 2650 A/mm2 • However, there was little manufacturing margin in meeting the RRR minimum of 60. • To meet the specs. the HT temperature had to be lowered to 650 °C/48h or lower. • For the LQ coils (0.7 mm) the reaction temperature was further reduced to 640 °C/48h so that the RRR of extracted strands could be above 60, and for HQ (0.778 mm), 650 °C/48h was used to maintain RRR > 100.

6. Arup Ghosh OST data 0.8/0.778 mm 108/127 strand 210C/48h + 400C/48h + 665C/50h

7. Arup Ghosh OST data 0.8/0.778 mm 108/127 strand 210C/48h + 400C/48h + 665C/50h

8. Arup Ghosh OST data 0.8/0.778 mm 108/127 strand Non-Cu %

9. OST Ti-Ternary Strand Production • 410 Kg from 12 billets have been delivered • 6 billets use standard Tin content • 6 billets use 5%-Reduced Tin content • Reduced Tin has significant impact on the RRR of the copper. • Marginal decrease in Jc. • Lower reaction temperatures needed for Ti-ternary than Ta-ternary wires for equivalent Jc 650°C instead of 665°C • Piece lengths have been very good; some billets drew down in a single piece. • For the standard Tin billets, we examined 640°C/48h to raise the RRR • For the Reduced Tin billets, 665°C/48hr was explored to further optimize Jc

10. OST data For Ti-Ternary at 0.778 mm 210C/48h + 400C/48h + 650C/50h < Jc >reduced by ~ 3% for the “Reduced-Sn” billets Reduced- Sn

11. OST data For Ti-Ternary at 0.778 mm 210C/48h + 400C/48h + 650C/50h 5% reduction in Sn content has strong influence on RRR Reduced- Sn

12. OST data For Ti-Ternary at 0.778 mm Reduced- Sn

13. OST Ti-Ternary Strand Production • 410 Kg from 12 billets have been delivered • 6 billets use standard Tin content • 6 billets use 5%-Reduced Tin content • Reduced Tin has significant impact on the RRR of the copper. • Marginal decrease in Jc. • Lower reaction temperatures needed for Ti-ternary than Ta-ternary wires for equivalent Jc 650°C instead of 665°C • Piece lengths have been very good; some billets drew down in a single piece. • For the standard Tin billets, we examined 640°C/48h to raise the RRR • For the Reduced Tin billets, 665°C/48hr was explored to further optimize Jc

14. Jc (12T) and RRR for 0.778 mm wire For the normal-Sn content billets we will use 640°C/48h reaction to raise RRR 0.85 mm 0.85 mm Reduced-Sn

15. Summary – Lessons Learned • 108/127 strand procurement from three different labs and evolving specification from LQ to HQ to QXF has made it hard to adequately oversee the various contracts and its production. 108/127 took a long time to be a stable product. • RRP wire can meet Ic spec with adequate margin • The “reduced-Sn” design change without making any other change in the processing has yielded high dividend in RRR control and should be implemented for all billets going forward. • Increased barrier thickness with “normal-Sn” content is another design change that is being developed for RRR control. I would approach this with caution pending sufficient experience. This design change may help in mitigating sub-element shearing during cabling. • Recommend dedicated RRR check of wire as they are delivered. Substantially lower cost compared to Ic test.

16. End of Presentation