1. Harold G. Kirk Brookhaven National Laboratory High-Field Solenoids for a MC Final Cooling System AAC 2012 Austin, Texas June 11-15, 2012

2. Harold G. Kirk 2 Muon Collider Parameters

3. Harold G. Kirk 3 The MC Cooling Scenario

4. Harold G. Kirk 4 Proposed Final Cooling Lattice

5. Harold G. Kirk 5 HTS R&D at BNL R. 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

6. Harold G. Kirk 6 Two Solenoids are being built and tested Solenoid #1 (Mid-sert) ID = 10cm OD=17cm 24 Pancakes Solenoid #2 (Insert) ID = 2.5cm OD=9.1cm 14 Pancakes

7. Harold G. Kirk 7 YBCO High Temperature Superconductor (HTS) The HTS Conductor 2G Superpower YBCO tape 4 mm wide 100μm thick 1μm YBCO (Yttrium Barium Copper Oxide) layer

8. Harold G. Kirk 8

9. 9 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

10. Harold G. Kirk 10 10 cm ID 2G Coils for Mid-sert Each coil has ~240 turns and uses 100 meter tape (maximum one splice) 100 mm

11. Harold G. Kirk 11 Test Results of 24 Coils at 77 o K Proof That A Large Number of 2G HTS Coils Can be Built and Tested without Degradation Individual tests for each col

12. Harold G. Kirk 12 Test of Half Mid-sert in LN 2 (12 pancakes) Overall performance is not limited by coils in the ends (where field perpendicular is largest). It is limited by 4 th coil of the total 12 (i.e. one near the middle). Coil voltages in individual coil as a function of current Coil numbers are counted from one end to another end

13. Harold G. Kirk 13 Test Results at 4.2 o K Measured 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 250 A ==> 9.2 T on coil 5 T on Axis Corresponds to 10T for full mid-sert

14. Harold G. Kirk 14 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.

15. Harold G. Kirk 15 7 double pancakes at 77 o K 7 double pancakes were built and individually tested at 77 o K. Voltage taps were attached every 50 turns. 15

16. Harold G. Kirk 16 Pre-test @67 o K – 77 o K Coil #11, #5 and #6 became resistive first These coils are near the middle of the solenoid not the at the edges

17. Harold G. Kirk 17 Summary of Test Results in LN 2

18. Harold G. Kirk 18 Test at 4.2 o K The critical current of this solenoid was only 16 A at 77 o K, however, current reached 285 A at 4.2 o K. At this current, the central field was over 15 T and the peak field on the conductor was over 16 T. 18 In LHeIn LN 2 gas He

19. Harold G. Kirk 19 Future Plans Step 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 Nb 3 Sn outsert coil with the goal of achieving 35T with an all superconducting solenoid.

20. Harold G. Kirk 20 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.

21. Harold G. Kirk 21 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

22. Harold G. Kirk 22 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 4.2 o K. A full length mid-sert delivering a 10T axial field The mid-sert and insert together can deliver 22T An outsert using Nb 3 Sn capable of 13-15T is proposed. outsert midsert insert

23. Harold G. Kirk 23 SUMMARY l Final cooling scenario for a Muon Collider requires 30-40T solnoids l An YBCO based HTS solenoid with an ID of 2.5cm has achieved and axial field of 15T l An YBCO based HTS solenoid with an ID of 10cm capable of 10T axial field is being tested l A Nb3Sn based solinoid with an ID of 20cm, capable of delivering >13T is proposed

24. Harold G. Kirk 24 Backup Slides