1. 1 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Dejan Trbojevic e-RHIC with non-scaling FFAG’s

2. 2 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Non-scaling FFAG for eRHIC Introduction to a concept of non-scaling FFAG Requirements for the eRHIC Arc single ring to accept 2.4-10 GeV electron beams 1.9 GeV Linac Going around detectors Matching the straights to arcs Summary and required future work

3. 3 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 What is the non-scaling FFAG? The first one is presently being built in UK: “EMMA” Orbit offsets are proportional to the dispersion function:  x = D x   p/p To reduce the orbit offsets to +-6 cm range, for momentum range of  p/p ~ +- 60 % the dispersion function D x has to be of the order of: D x ~ 6 cm / 0.6 ~ 10 cm The size and dependence of the dispersion function is best presented in the normalized space and by the H function:  = D x /  x and  = D’ x  x +  x D x  x with H:H =  2 +  2

4. 4 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Basic properties of the NS-FFAG A. Particle orbits B. Lattice

5. 5 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Muon acceleration Concept introduced 1999 at Montauk meeting –Trbojevic, Courant, Garren) using the light source lattice with small emittance minimized H function - Extremely strong focusing with small dispersion function. - large energy acceptance. - tunes variation - very small orbit offsets - small magnets Basic properties of the NS-FFAG

6. 6 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Recent example of the muon acceleration collaboration with the Muon.inc Orbits magnified 100 times From 2.5 GeV- 10GeV

7. 7 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 New Concept: Multipass Linac with racetrack FFAG Chicane Non-scaling FFAG arc 20 Cavities Non-scaling FFAG arc

8. 8 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Layout of the RHIC tunnel

9. 9 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Possible locations of the magnets

10. 10 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Previous solution (PAC07)

11. 11 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Previous work on the non-scaling FFAG in RHIC tunnel

12. 12 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Layout of the Arc in RHIC

13. 13 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Design of the arcs – from the densely populated FODO cells for the 2 - 10 GeV electrons N=648 cells L=3.6965 m R1=381.23249 m L BD =1.6 m L QF =1.0 m For the  p/p=[0,-80 %] B BD = + 0.078 T B QF = + 0.199 T GF= 9.15 T/m GD= - 5.4 T/m @ electron energy=3.8 GeV B max =0.078 - 5.4  -0.048)=-0.34 T B max =0.199 +9.15  0.069)=- 0.43T r=381.23 m 762.46 m Orbits are magnified 1000 times

14. 14 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Design of the arcs – from the densely populated FODO cells for the energy range of 2.4 -> 10 GeV electrons Orbits in the arc cell – there are 648 cells in the whole ring B d /2 BfBf 0.8 m 1.0 m 0.5483 m 3.696228 m 44 mm

15. 15 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Design of the arcs – from the densely populated betatron functions vs. momentum

16. 16 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Design of the arcs – from the densely populated betatron functions vs. momentum

17. 17 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 The linac – triplets with cavities 10 GeV 2.4 GeV Qd Qf Cavity 7.393 m G f =15.8 T/m G d =-10.4 T/m

18. 18 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Superconducting linac: Betatron Function dependence on energy

19. 19 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 New concept of the linac – Tunes per Linac cell

20. 20 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Matching cell – arc to linac The matching cell length is: L=2  3.696 m = 7.393 m

21. 21 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Design of the large cells – match to the linac 7.393069 m 0.8 m 1.0 m 0.8 m 1.0 m Orbit offset are identical to the arc orbit offsets

22. 22 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Design of the arcs – Matching to the linac

23. 23 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Larger cells to match to linac from arcs Lp_cell Ln_cell Lp_cell Orbit offsets are zero         

24. 24 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Creating the 4.6 m around the detectors 4.6 meters 4.6 m

25. 25 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 229 meters Separation Of 4.6 meters The whole ring with two straight sections - linacs

26. 26 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 229 meters Separation Of 4.6 meters The whole ring with two straight sections - linacs

27. 27 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 The linac

28. 28 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Time of flight – Path length dependence on energy

29. 29 Dejan Trbojevic EIC Collaboration Meeting, Hampton University, Virginia May 19, 2008 Summary: The non-scaling FFAG concept could be applied for eRHIC within the existing tunnel. The non-scaling FFAG arc has been constructed to accept in a single pipe electrons in energy range from 2.4 – 10 GeV with a circular 10 GeV electron orbit, maximum orbit offsets of ~70 mm for the lowest energies, and with the maximum magnetic fields of 0.4 T at the lowest energy. The magnetic field strengths for the 10 GeV electrons are B max < 0.2 T. A new concept of energy recovery linac with small changes in the betatron functions for the six times in energy range has been presented for the first time. Possibilities of bypasses and time of flight adjustments have been explored. Matching between the arcs and straight sections for linac needs to be improved. A special beam line to send electrons towards the detector need to be designed.