NEWS 4 th Annual Meeting – October 24, 2018

1. NEWS 4th Annual Meeting – October 24, 2018 NEWS Work Package 7Advanced Superconducting Technologies for Particle AcceleratorsEmanuela Barzi, Fermilab

2. Summary of WP7 Tasks T6.1: Build and install the superconducting modules of the Mu2e Transport Solenoid (INFN, FNAL). The modules are in construction at the ASG Superconductors in Italy under a FNAL contract, with the active collaboration and supervision of INFN personnel. T6.2: Design and build a 16 T Nb3Sn accelerator dipole (FNAL, INFN). This includes coil design studies, magnetic analysis, design of mechanical structure for the 4-layer coils, and coil stress analysis at the three stages of magnet operation. T6.3: Optimize state-of-the-art electrochemical techniques (US patent pending) for Nb3Sn thin layer deposition on Nb and on Cu (POLIMI, FNAL, Faraday). Applications include performance improvement of superconducting Nb3Sn wires for High Field Magnets, Radio-frequency cavities, superconducting magnetic shields. E. Barzi, NEWS 4th Annual Meeting – October 24, 2018

3. WP7 Milestone & Deliverables MS9 : Mu2e Transport Solenoid Constructed [Month No. 20] D7.1 : 16 Tesla Dipole Designed [Month No. 24] Verify the design studies, magnetic analysis, mechanical structure design, coil stress analysis at the three stages of magnet operation (i.e. room temperature, after cooling down at the temperature of operation of 4 K, and at nominal magnetic field operation). D7.2 : Nb3Sn Deposition Technique Optimized on Niobium and Copper [Month No. 36] State of the art electrochemical techniques will be optimized to achieve the best uniformity of the deposit across the surface, the best purity and improve the adhesion of the film. Samples will be experimentally characterized. E. Barzi, NEWS 4th Annual Meeting – October 24, 2018

4. Results & Status of 16 T Dipole Design (T6.2) • Magnet design limit is determined by mechanical constraints and it is 15 T. • The challenge to solve for the INFN-FNAL collaboration is to push the design limit of these magnets to their superconducting potential (or Short Sample limit). To design and build a 16 T Nb3Sn superconducting dipole, the design limit needs to be at least 17 T. E. Barzi, NEWS 4th Annual Meeting – October 24, 2018

5. Magnet Components STATIC LOAD IN ELASTO-PLASTIC REGIME Four magnetic cryostats with up to 15T/17 T background field, and with cold apertures between 64 mm and147 mm are connected to new vent and vacuum systems. 10-STACK SAMPLE Five ovens up to 1500◦C for heat treatment in Argon and in Oxygen. E. Barzi, NEWS 4th Annual Meeting – October 24, 2018

6. Sub-modeling of 10-stack tests ASSUMPTIONS ■ Elastic perfectly plastic, aside from Nb3Sn (elastic only) ■ Isotropic ■ No keystone and lay angles ■ No pre-stress 6

7. Single Cell Model PARAMETERS FOR COMPARISON ■ Stress and strain (equivalent) behavior ■ Stress and strain maxima ■ Displacement along horizontal direction (UX) ■ Displacement along vertical direction (UY) 7

8. Young modulus of composite • Was obtained using an orthotropic transversally isotropic material model: • E = E1 = E2 •  =12 = 21 • E|| = E3 • 13 = 23 • G13 = G23 8

9. Results & Status of Nb3Sn Thin Films on Nb (T6.3) Dozens of Nb3Sn film samples were produced on Nb substrate and characterized for SC properties at FNAL. Tc compared with old [1] samples  Electrochemical plating setup at FNAL Ic||(4.2K, B) compared with old [1] samples  SC Properties of best new and old [1] Nb3Sn films E. Barzi, NEWS 4th Annual Meeting – October 24, 2018

10. Bath Composition for the Three Steps STEP 3 STEP 2 STEP 1 State-of-the-art Nb3Sn Films by Electro-chemical Deposition, Oct. 9 2018

11. Pictures of Samples at Each Step STEP 1 STEP 2 STEP 3 Samples for SC characterization Two-inch discs for surface inductance measurements at JLAB State-of-the-art Nb3Sn Films by Electro-chemical Deposition, Oct. 9 2018

12. Example – Sample No. 23 Electron Probe Microanalysis (EPMA) for elemental quantitative analysis with Wavelength-Dispersive Spectroscopy (WDS) State-of-the-art Nb3Sn Films by Electro-chemical Deposition, Oct. 9 2018

13. Characterization – Sample No. 23 SQUID Tc0=17.6K (NIMS) DC Tc0=17.5K (FNAL) M-H curve obtained with SQUID magnetometer (NIMS). Hc1(4.2 K) = 600 Oe. State-of-the-art Nb3Sn Films by Electro-chemical Deposition, Oct. 9 2018

14. Cylinders Coating – In progress State-of-the-art Nb3Sn Films by Electro-chemical Deposition, Oct. 9 2018

15. Prospects for SRF State-of-the-art Nb3Sn Films by Electro-chemical Deposition, Oct. 9 2018

16. Conclusions MS9 : Mu2e Transport Solenoid Constructed [Month No. 20]: Expected by Nov. 2018, i.e. Month 17, if no delays. D7.1 : 16 Tesla Dipole Designed [Month No. 24] Mechanical design studies are ongoing. PhD student secondments are being planned to accelerate work. D7.2 : Nb3Sn Deposition Technique Optimized on Niobium and Copper [Month No. 36] - Characterization of Nb3Sn film on Nb substrate is ongoing. - Polimi will be leading the technique for Nb3Sn deposition on Cu substrate. Publications • “Nb3Sn Thin Film for the Production of Higher Gradient SRF Cavities at Reduced Costs”, S. A. Kahn, M. A. C. Cummings, Muons, Inc., E. Z. Barzi, S. Falletta, D. Turrioni, Fermilab, A. Kikuchi, NIMS, Tsukuba, Japan, Proceedings of the 9th International Particle Accelerator Conference (IPAC'18), Apr. 29-May 4, 2018, Vancouver, British Columbia, Canada. • “Nano-engineering Nb3Sn Thin Films to Improve Wire Performance and Reduce Cost”, S. A. Kahn, M. A. C. Cummings, Muons, Inc., E. Z. Barzi, Proceedings of the 9th International Particle Accelerator Conference (IPAC'18), Apr. 29-May 4, 2018, Vancouver, British Columbia, Canada. • “An Innovative Nb3Sn Film Approach and its Potential for SRF Applications”, E. Barzi, C. Ciaccia, S. Falletta, D. Turrioni, FNAL, A. Kikuchi, H. Hayano, T. Saeki, H. Ito, G. Eremeev, A.-M. Valente-Feliciano, R. L. Geng, R. Rimmer, Proceedings of the 29th Linear Accelerator Conference (LINAC18), Sep. 16-21, 2018, Beijing, China. E. Barzi, NEWS 4th Annual Meeting – October 24, 2018