1. PROGRESS REPORT OF A NLNS-FFAG ADS MAGNET
F. Meot, W. T. Weng, W. Z. Meng, BNL
C. Johnstone, PAC
PASI-II, RAL, UK
April 3-5, 2013

2. OUTLINE Introduction Machine Parameters Magnet Parameters and Design
Cost Estimate of the Magnet
Possible Iteration
Summary and Conclusion

3. Ingredients of a Complete FFAG
Acceptable Lattice Design( tunes, isochronous,
dynamical aperture, component space, etc., …)
RF System and Power Source
Magnet System and Power Supply
Injection/Extraction
Ion source and Front End Systems
Beam Dynamics( space charge, loss rate, radiation protection, .. ) and Performance Simulation
Manufacturing process and cost
This report focus on Magnet design performed
at BNL

4. Performance Requirements

5. Performance Requirements-2

6. Ring Layout

7. Radius

8. Orbit from Injection

9. Magnet Length

10. BNL’s Magnet Cost Study

11. Input Parameters

12. OPERA 2-D and 3-D Run Preliminary magnet parameters:
Gap: cm (1.75 center (R=x=630 cm)
(Required: 2 R=550 cm; 1.5 R=710 cm)
Bending angles: at larger radius (for extraction energy) is 60º;
at smaller radii could be much less than 60º
Pole width: 185 cm (along the radial direction)
Yoke thickness: 105 cm (inner); 85 cm (outer); 94 (top); with cuts
Ampere-turn required: 36,400 A-t (per coil) ( giving ~ 20% saturation)
Nominal coil cross-section: 10 (H) x 28(V) cm (overall J = 130 A/cm**2);
(assuming water cooled; 50% volume copper)

13. Flux Plot

14. Field (By) plot (unit: cm, gauss) Required B~1
Field (By) plot (unit: cm, gauss) Required B~1.5 T at R = 550 cm and B~1.9 T at R = 710 cm

15. Steel Shape Steel (1006) estimate: Weight ~5.17E5 kg
(including “field clamps”)
Envelope size:
Height 2.56 m
Width 3.99 m
Arc-Length 9.17 m (outer)
4.99 m (inner)
Field Clamp

16. Coil Configuration

17. Steel Assembly Drawing

18. Rough Cost Estimate Based on 8 pieces machined core assembly
of a 500 T magnet, it cost about $4.5M.
A FFAG ring of 6 magnets will cost $27M.
Worry about effects of excessive weight on manufacturing, assembly, transportation, floor loading, and cost indicates the need for possible improvement, through iterative process with lattice, Inj/Ext, and RF design.

19. Possible Improvements
More Cells( 8 or 10 )
Smaller Gap
Lower Energy
S. C. Magnet

20. Conclusion and Future Works
A methodology has been established to do magnet design and cost estimate. Possible future works
Are:
Finalize lattice and Magnet Parameters
Optimize Magnet Design, including proper
Chamfer and Shims with 3-D code
Confirm Lattice with ZGOUBI Code
Build a Prototype Magnet

21. References
S. L. Sheehy, C. Johnstone, “A 1 GeV CW FFAG High Intensity Proton Driver”, IPAC2012
C. Johnstone, P. Snopok, F. Meot, W.T. Weng, “1 GeV CW Non-scaling FFAG For ADS”, IPAC2012
F. Meot, et. Al., “Variable Energy Protontherapy FFAG Accelerator”, EPAC2008