Extraction from the FFAG

1. Extraction from the FFAG David Kelliher ASTeC/STFC/RAL

2. Contents Introduction Extraction schemes Magnet apertures Effect of special magnets UKNF Plenary meeting, Dept of Physics, Lancaster University

3. Introduction UKNF Plenary meeting, Dept of Physics, Lancaster University

4. Linear NS-FFAG Motivation for use in muon acceleration • Allows fast acceleration - no waiting around for magnets to ramp • Large dynamic aperture - linear magnets + high degree of symmetry • Multiple passes through RF • Orbit excursion and hence magnet aperture smaller than in the case of a scaling FFAG • No multiple arcs and complex switchyard as in RLA • Potential Issues • Non-zero chromaticity leads to emittance blow up leading to increase in momentum spread • Deterioration of the beam due to “Resonance” crossing • Injection/Extraction difficult due to short drifts. UKNF Plenary meeting, Dept of Physics, Lancaster University

5. Candidate lattices (J. Scott Berg) UKNF Plenary meeting, Dept of Physics, Lancaster University

6. Beam dynamics using Zgoubi J. Pasternak

7. Extraction schemes UKNF Plenary meeting, Dept of Physics, Lancaster University

8. J. Pasternak - Horizontal extraction with 10 kickers m m Parameters: 10 kickers – 1.4 m, 0.125 T and septum – 1.4 m, 4 T. J. Pasternak

9. Vertical extraction – 6 kickers • Kick vertically with 6 kickers at 0.067 T in consecutive drifts • Septum at 2T • Gap between kicked and circulating beam at septum entrance is 2cm • Magnets immediately before the septum require large aperture UKNF Plenary meeting, Dept of Physics, Lancaster University

10. Extraction with 6 kickers (J. Pasternak) • Kickers – 0.08 T • Mirror symmetric • 4T Septum UKNF Plenary meeting, Dept of Physics, Lancaster University

11. Vertical extraction – 4 kickers • Kick vertically with 4 kickers at 0.096 T in consecutive drifts • Again magnets immediately before the septum require large aperture UKNF Plenary meeting, Dept of Physics, Lancaster University

12. Magnet apertures UKNF Plenary meeting, Dept of Physics, Lancaster University

13. Tracking the beam envelope • Find closed orbit then use Zgoubi MATRIX command to find twiss parameters. • Starting at track on particle through the cell many times to generate points on the 30  mm phase space ellipse. • Start at these points on the ellipse and track many particles through the cell once. The trajectories describe the beam envelope. UKNF Plenary meeting, Dept of Physics, Lancaster University

14. Tracking the beam envelope(injection/extraction) Horizontal beam envelope Vertical beam envelope UKNF Plenary meeting, Dept of Physics, Lancaster University

15. Magnet apertures – circulating beam F D 31.7 cm 14.4 cm UKNF Plenary meeting, Dept of Physics, Lancaster University

16. Special magnet apertures F D 41.6 cm 39.06 cm UKNF Plenary meeting, Dept of Physics, Lancaster University

17. Effect of special magnets UKNF Plenary meeting, Dept of Physics, Lancaster University

18. Closed orbit at injection energy UKNF Plenary meeting, Dept of Physics, Lancaster University

19. Closed orbit distortion due to special magnets Peaks in closed orbit distortion at integer tunes Calculate accelerated orbit distortion UKNF Plenary meeting, Dept of Physics, Lancaster University

20. Beta beating due to special magnets UKNF Plenary meeting, Dept of Physics, Lancaster University

21. Conclusion • Future Work • Injection • Look at accelerated orbit distortion • Other candidate lattices Vertical extraction from the FFAG looks more feasible than horizontal extraction Requires large aperture magnets near septum Effect of these “special” magnets on beam dynamics, e.gc.o.d and beta beating, under investigation UKNF Plenary meeting, Dept of Physics, Lancaster University