Hadron Collider Breakout Session Summary

1. Hadron Collider Breakout Session Summary D. Schulte, L. Bottura, B. Goddard, M. Jimenez

2. Programme

3. Pleas for Help and a Promise …

4. Conclusion • Please help by • signing up for the email lists • FCC-hh-design@cern.ch • FCC-hh-beamdynamics@cern.ch • FCC-hh-injectors@cern.ch • FCC-hh-technologies@cern.ch • FCC-hh-magnets@cern.ch • reviewing and improving our parameters • helping to prepare choices for the baseline design • preparing the future collaboration Will have video meetings Will provide a list of critical issues Actual work needed already now

5. Some Volunteers …

6. F. Petrov

7. A. Seryi

8. S. Chattopadhyay, Cocroft

9. Some Things to Address …

10. M. Jimenez • Technology Challenges and Breakthroughs • Have a list with technical challenges that need to be addressed • And breakthroughs that are required (will push technology in general) • Very good place to find your favorite subject for the collaboration

11. M. Schaumann • First Look at the Ion performance • Ion luminosity seems good using LHC injector chain • Main luminosity limitations are from the injector chain • Ions place a significant constraint on interaction region design

12. Magnets …

13. Breakout-magnets: summary L. Bottura Thoughts on a Friday night Valentine’s day, 2014

14. Superconductors • Material research: the FCC superconductors are not looking like anything we know from the past, nor HL-LHC. The present potential for improvement is in the range of 20 %... 50%, not enough • 5 years target: work on carrier density, pinning, grains to improve performance in present high-field materials • 10 years target: consider other materials (Fe-based, MgB2, round REBCO) • Very large scale material requirements for LTS (10x ITER Nb3Sn production) and HTS (much above anything done so far) • Actions proposed: • Launch a focussed 16 T Nb3Sn conductor program (factor 2 Jc at 18 T) • Pursue work on HTS materials to make them suitable for accelerator magnets • Consider other issues (protection, filaments/field quality, homogeneity and yield for low cost) • The LTHFSM Workshop could be an incubation center for material R&D • Open questions: • Are exotic materials (Fe-based SC) a realistic candidate for R&D ?

15. Magnet technology • HL-LHC and companion HFM programs are exploring the 11...13 T operating field range, with ultimate field levels that are relevant to FCC (Fresca2), much experience can be drawn from these programs • Is there a “barrier” at 15 T, or is this only perceived as such ? • In the 16…20 T field range it is not clear what is the best geometry (block, cos-theta, CCT), examine them all • The present design margin, in the range of interest, is very large (20 %) – how to decrease it ? • Training, we cannot afford so many (> 10) quenches • Magnet protection is an issue both for LTS (energy density vs. JE) and HTS (propagation speed and detection)

16. Matters of optima • Tunnel length, operating field and temperature, SC material selection, are parameters affecting greatly the location of the optimum (minimum cost, maximum performance) • Other constraints (e.g existing infrastructure), and benefits (e.g. the value of R&D at the field frontier) must be considered

17. My Comments on Magnets • Very interesting for a non-expert • Much to be learned, thanks for the insight • Very active field • Quite some interaction with other experts required for optimisation • Should not forget the insertion magnets • Goal for b*=0.1m (Rogelio Tomas) • Challenges magnets • But helps for overall design • Faster ramp of LHC magnets (O(3minutes)) appears possible • But some studies to be performed • Many issues of LHC re-use as injectors • Need to evaluate aperture needs for injector in 100km ring • Added some slides in the reserve on the different individual talks

18. In practice • Define a direction for relevant R&D, set challenging (but realistic) targets, describe impact of this technology on other fields, and describe a development plan into a roadmap document to be contributed by the collaborators and edited within the scope of the FCC study • This roadmap document will become a reference for future accelerator magnets R&D proposals (e.g. US-DOE, Horizon 2020), and can be used as a basis of collaboration for FCC design and hardware R&D work • Time scale: 3 months (tough !)

19. Conclusion • First volunteers • Also some private discussions with no presentation • List of critical items to work on is progressing • Technical items shown by Miguel • Promised to produce first draft soon • Very good discussion on magnets • Progress visible • Still new design ideas • Workplan in preparation • Will continue with video meetings Many thanks to the speakers and the chair Mike Syphers for almost keeping the schedule And to all participants

20. The Summary that I Cannot Show

21. Some Key Points from the Talks D.S., Brennan Goddard

22. Magnets David Larbalestier: LTS and HTS Material Issues for 16 and 20 T Applications • Nb3Sn is still plan A • But have HTS cable, still issues to be addressed AmaliaBallarino: Material R&D toward 16-20T horizon • ITER first large-scale user of Nb3Sn(800 A/mm2 at 12 T, 4.2 K): 500t • HL-LHC needs 2500 A/mm2 at 12 T, 4.2 K • FCC with 16 T magnets: 4,500 tons of Nb3Sn and 10,000 tons on NbTi • FCC with 20 T: 1,400 tons HTS, 6,300 tons Nb3Sn, 11,000 tonsNbTi

23. Magnets Paolo Ferracin: Overview of HiLumi low beta and FRESCA2 magnets • FRESCAII is block magnet to test HTS inserts • Forces and stresses on coil for FRESCA2 comparable to 16-20 T coils MikkoKarpinnen: 11T Experience • Many lessons learned from the 11T work for the HL upgrade Steve Gourlay: SC Magnet Developments Towards 16T Nb3SN Dipoles • A slanted solenoid design looks attractive and should be tested

24. Magnets Ezio Tedesco: Design Options for the 15-20T Range • We should review the design margin, it cost a lot Peter McIntyre: Low Cost Magnet Design • We should think about the cost not focus only on the field AttilioMilanese: Injector Magnet Considerations • The LHC magnets can be made to ramp up in 3 minutes, with some sissues to be addressed Rogelio Tomas: Insertion Magnet Challenges • Insertion magnets are also important • Should aim for b=0.1m

25. David Larbalestier: LTS and HTS Material Issues for 16 and 20 T Applications

26. 16 T for 100 TeV in 100 km AmaliaBallarino Cosine theta type magnet, Nb-Ti and Nb3Sn. Bore  = 40 mm • Material R&D toward 16-20T horizon • ITER will be first large-scale (500t) user of Nb3Sn, with 800 A/mm2 at 12 T, 4.2 K • HL-LHC needs 2500 A/mm2 at 12 T, 4.2 K • Total amount of conductor neededfor 16 T magnets in 100 km collider wouldbeabout 4,500 tons of Nb3Sn and 10,000 tons on NbTi • For 20 T in 80 km tunnel, 1,400 tons HTS, 6,300 tons Nb3Sn, 11,000 tonsNbTi • Productionquantity of HTS is hugebytoday'sstandards - tooearly to evenstartguessingaboutcost 4300 tons Nb3Sn + 10200 tons of Nb-Ti 9 times Nb3Sn for ITER and Nb-Ti for LHC A. Ballarino, CERN

27. Paolo Ferracin • Overview of HiLumi low beta and FRESCA2 magnets • Low-beta is 7 m long magnet, accelerator quality coils and magnet at 12 T operational field level, Nb3Sn, cos2theta • FRESCA2 is aiming at 15 T dipole field for HTS insert tests, not accelerator quality, block coils • Forces and stresses on coil for FRESCA2 comparable to 16-20 T coils

28. MikkoKarpinnen • 11T Experience • Many lessons learned from the 11T work for the HL upgrade • Cannot list them here • Useful input for future R&D

29. Steve Gourlay The Canted Cosine-Theta (CCT) Magnet • SC Magnet Developments Towards 16T Nb3SN Dipoles • Different winding scheme potentially could make magnets cheaper by reducing stress • Paradigm change? • This seems well worth exploring “perfect” current distribution Superconducting Magnet Group - S.Caspi

30. Design Options for the 15-20T Range • Need to review required margin Ezio Tedesco

31. Peter McIntyre • Low Cost Magnet Design • Should consider an overall cost optimisation leaving the dipole field as a free parameter • 5 T 10 K dipole is excellent candidate for rapid-cycling injector

32. Injector Magnet Considerations • Different options of injector magnets investigated • SPS with Nb3Sn magnets takes 5-10 minutes to ramp, require 25 ramps • LHC magnets can likely ramp faster than now with some modifications in the power supplies (2-3 minutes) • Option with normal magnets in the 100km ring need to be reviewed for impedance and required aperture Attilio Milanese

33. R. Tomas • Insertion Magnet Challenges • The interaction region contains challenging magnets • They can drive the system design • The interaction region impacts the overall design strongly(the beta-function determines the required beam current) • Should aim for beta-function of 0.1m • High field magnet development essential even if cost is high