1. 1 Project X Workshop November 21-22, 2008 Richard York Chris Compton Walter Hartung Xiaoyu Wu Michigan State University

2. 2 Outline SRF capability Elliptical β=0.8 R&D status Interests –Elliptical β=0.8 completion –Alternative Lattice Elliptical structures from ~150 MeV (β  =0.61) Summary

3. 3 SRF History

4. 4 SRF Infrastructure

5. 5 SRF Cavities Quarter & Half WaveElliptical β =0.81

6. 6 SRF Cryomodules cold massmu-metal shield MLI top plate 77 K shieldvacuum vessel

7. 7 SRF Cryomodules Elliptical Quarter and Half Wave

8. 8 MSU 3 MeV/u Linac Project Design, fabrication, and assembly 3 Cryomodules –16 Cavities (quarter-wave) Fabrication, Processing, Vertical Certification –16 Power Couplers Assembly and Conditioning –16 RF drive systems and Controls –8 Solenoids (9 Tesla) Mapping and Shielding

9. 9 MSU Capacity & Capability Design –Beam Dynamics –Electrical Engineering –Mechanical Engineering –Material Science Fabricate & Test –SRF cavities (~25 per year) –Superferric magnets –Cryomodules (~6 per year)

10. 10 β  = 0.81 Motivation Efficient acceleration between β  0.7 and β  0.9. Benefit from experience with β < 1 acceleration (SNS) and minimize technical risk. Cell shape compatible with rigorous surface preparation. Maximum overlap with ILC. Same as TTF/ILC cavity: frequency; beam tube diameter; helium tank design; RF coupler design; tuner; cryomodule design; RF system; fabrication steps; preparation steps, cleanliness requirements. Investigate potential of large grain niobium for improved performance and cost reduction.

11. 11 β = 0.81 Design Four single-cell prototype cavities –2 fine grain –2 large grain Two 7-cell cavities fabricated –1 fine grain –1 large grain Electric field lines from SUPERFISH TTF, SNS, and RIA cell shapes Cell shape is similar to SNS β = 0.81 cavity

12. 12 β = 0.81 R&D Fabrication Processing

13. 13 β = 0.81 RF Test Results Single-cell testing done in collaboration with JLab Highest gradients reached Fine Grain –E a = 25 MV/m –E P = 54 MV/m, B P = 131 mT Large Grain –E a = 28 MV/m –E P = 62 MV/m, B P = 148 mT 2 K after Ti treatment 2 K after Ti treatment & bake-out

14. 14 β = 0.81 Future Work

15. 15 Beam Dynamics SC linac beam dynamics studies since 2000 –RIA driver linac, ISF, FRIB, ReA3, ReA12 Advanced simulation tools –RIAPMTQ, IMPACT –PARMELA, COSY INFINITY, DIMAD, MAFIA, ANALYST, SUPERFISH, KOBRA-3D, LANA, etc. MSU High Performance Computing Center –Parallel capability –High statistics beam simulations

16. 16 Project X Alternative Lattice Motivation Use Elliptical structures from 150 MeV Figures of merit favor elliptical for β >0.55 Possibility to reduce cost & risk Possibility to increase ILC overlap β = 0.61 1.3 GHz Elliptical β = 0.6 0.325 GHz Spoke

17. 17 Project X Alternative Lattice Baseline linac structure Alternative linac structure SSR-1SSR-2 TSR S-BETA ILC 325 MHz 1.3 GHz W (MeV) 10 32 132 418 1200 SSR-1 SSR-2 S-BETA-1 S-BETA-2 ILC 325 MHz 1.3 GHz W (MeV) 10 32 150 400 1200

18. 18 S-BETA-1 Cavity Parameters GG 0.6 Number of cells 6 Frequency1.3 GHz Peak surface field 52 MV/m Number of resonators 48 Number of cryomodules 6 Cryomodule length 9.2 m

19. 19 S-BETA-2 Cavity Parameters GG 0.81 Number of cells7 Frequency1.3 GHz Peak surface field 52 MV/m Number of resonators 64 Number of cryomodules 8 Cryomodule length 11.7 m

20. 20 Focusing Lattice RT and SC quadrupoles –Gradient: 12 T/m Cavity SC Quads RT Quads

21. 21 Preliminary Beam Dynamics Studies (1) Initial phase space at 150 MeV  xy,n ~ 2.5  mm-mrad  L ~ 30  keV-ns Final phase space at 1.2 GeV No emittance growth

22. 22 Energy Beam envelope Longitudinal phase width Preliminary Beam Dynamics Studies (2)

23. 23 Preliminary Beam Dynamics Studies (3) Longitudinal acceptance at 150 MeV~ 210  keV-ns Emittance-to-Acceptance ratio ~ 7

24. 24 Lattice Comparison  BaselineAlternative TSRS-ILCS1-ILCS2_ILC GG 0.60.810.60.81 N(cell)4867 N(cavity)42564864 N(cryo)7778 Epeak30 MV/m 52MV/m Voltage9.31 MV 17.72 MV7.31 MV15.84 MV W(in)120 MeV 420 MeV150 MeV400 MeV W(out)420 MeV 1.2 GeV400 MeV1.2 GeV Alternative

25. 25 Summary Capabilities –Beam dynamics –Alternative analyses - value engineering –Design →Fabricate →Test SRF cavities SRF systems (cryomodules) Superferric magnets Near term interests –Apply capabilities to contribute to optimization and concomitant R&D –E.G. lattice optimization, cavity & cryomodule prototyping, technology transfer