Update on recent developments in FFAG accelerators

1. Thusday, November 2, 2006 Update on recent developments in FFAG accelerators Dejan Trbojevic Brookhaven National Laboratory, Upton, NY, USA Introduction: A Very Close Connection Between CYCLOTRONS and FFAG’s. Scaling and Non-scaling FFAG’s. Developments in the FFAG field during the last year: Acceleration with the harmonic jump in the FFAG’s for protons. More designs of SPIRAL FFAG. FFAG gantry – accepts and transfers the required energies with fixed field. Race track non-scaling FFAG. Problems found in accelerating muons at the top of the RF - the path length dependence on amplitude. Recent FFAG workshops (Kyoto, Port Jefferson) and reports: Y. Morri, E. Keil, A. Sessler, F. Meot, S. Ruggiero, S. Berg, S. Machida, C. Johnstone, S. Koscielniak, R. Palmer, Al Garren, M. Craddock, R. Edgecock, E.D. Courant, M. Blaskiewicz, D. Neuffer, M. Berz, C. Prior, G. Rees, D. Trbojevic etc. Major areas of interest: Interest for medical applications (KEK commissioning, recent publications: Phys. Rev. S. Topics, NIMA). Muon Acceleration and cooling (PRISM commissioning). Developments of a non-scaling FFAG model (EMMA, EUROFFAG, RASCAM, in US three SBIR contracts) . proton and heavy ion acceleration (including may be RIA – EPAC06 paper) electron acceleration (e-RHIC, industrial applications). Summary

2. A little bit of history: FF but not FFAG [Slides from the Rick Baartman presentation: ‘Cyclotrons: Classic to FFAG’ – 2004] Thomas They are also FF (Fixed Field) with weak focusing – no opposite bend but not AG (Alternating Gradient) with strong focusing –with opposite bend.

3. From CYCLOTRONS to FFAG’s:

6. MURA-KRS-6 Phys.Rev. 103, 1837 (1956) November 12, 1954 K. R. Symon: The FFAG SYNCHROTRON – MARK I The first SCALING FFAG DR~60-100 cm N=2p/(N1+N2) r = r1sin(q/2)/sin(b/2)=r q/b

7. Francois Meot slide

8. Second model. First SPIRAL Sector MARK V (1957)

9. Yoshimary Mori at EPAC06

11. Y. Mori – EPAC 06

12. Scaling FFAG –Non scaling FFAG B = Bo+r Go B =Bo(r/ro)k • Scaling FFAG properties: • Zero chromaticity. • Orbits parallel for different dp/p • Relatively large circumference. • Relatively large physical aperture (80 cm – 120 cm). • RF - large aperture • Tunes are fixed for all energies. • Negative momentum compaction. • B =Bo(r/ro)k non-linear field • Non-Scaling FFAG properties: • Chromaticity is changing. • Orbits are not parallel. • Relatively small circumference. • Relatively small physical aperture (0.50 cm – 10 cm). • RF - smaller aperture. • Tunes move 0.4-0.1 in basic cell. • Momentum compaction changes. • B = Bo+r Go linear field

13. Proton therapy 31-250 MeV

16. Developments in the FFAG field during the last year: • Acceleration with the harmonic jump in the FFAG’s for protons- Sandro Ruggiero • [Kolomensky 1953)

17. The Harmonic Jump Acceleration the whole acceleration is all the time above transition If the whole acceleration bellow transition.

18. Acceleration with the harmonic number jump

19. Carbon/proton therapy facility design with non-scaling FFAGreviewed for Phys. Rev. Special Topics

20. Harmonic jump acceleration applied for three non-scaling FFAG rings for carbon/proton therapy

21. Harmonic number jump applied in carbon/proton therapy non-scaling FFAG The energy gain DE in a turn is adjusted such that the change in cbcauses a change of the revolution period by an integral number of rf cycles, and hence corresponds to an integral step Dh in h. Since: Db/b=-Dh/h and db/dg = 1/bg3 DE = - Eob2g3Dh/h, Eo is the rest energy of the particle The smallest DE is achieved with Dh = -1 and at large h. At fixed Dh, DE increases rapidly during acceleration. Its variation can be reduced by starting acceleration with |Dh|>>1, gradually decreasing |Dh| , and switching to Dh = -1 towards the end. h RF system parameters: f ~ 1.3 GHz initial hiharmonic number final hf harmonic number initial step |Dh| number of turns maximum circumferential voltage V .

22. The harmonic number jump application for the carbon/proton therapy accelerator The harmonic number h decreases during acceleration, since the revolution period decreases because of the increasing speed cb.The number of turns is significantly smaller than the difference (hi - hf ), because of the initial step |Dh |> 1, and much smaller than it is in a synchrotron. The energy gain per turn varies by less than a factor of two, but is much larger than in a synchrotron. The high rate of acceleration ensures fast crossing of the resonances. The bunches are arranged in a train. The train occupies a fixed time interval DT, which is a small fraction of the revolution period at injection into Ring 1 for H+ and into Ring 2 for C6+. Variation of the harmonic number during acceleration Carbon acceleration From 68 -> 400 MeV/u h Variation of the circumferential voltage Vc/MV

23. Spiral scaling FFAG magnets r=2.14m B = Bo + r G -20% < dp/p < +50% E k_min < Ekc < E k_max 77.5 <118.4 < 250 MeV

27. Spiral scaling FFAG magnets –Francois Meot study Francois Meot: Spiral Stability study

28. Rotated Linear Magnet q=p/4

29. Non-scaling FFAG single magnets with linear fields 24 magnets

33. R. Bartmaan T. Suzuki A. Sessler S. Kahn Y. Kuno S. Berg R. Palmer D. Trbojevic S. Koscielniak E.D. Courant M. Craddock A. Garren A. Bogarz E. Keil Y. Mori C. Johnstone S. Machida S. Ruggiero

37. New Spiral scaling FFAG

38. 150 MeV FFAG at KEK

40. KEK beam extraction

41. Race track non-scaling FFAG

42. RIA acceleration with non-scaling FFAG’s instead of linac

44. Non-scaling FFAG for RIA: lattice parameters

45. Magnet profiles in non-scaling FFAG for RIA

46. Scott Berg: Accuracy in codes designing the FFAG

47. ERLP Cell of EMMA FFAGs in the UK • British Accelerator Science and Radiation Oncology Consortium: -Proposal to UK Basic Technology programme: o Build EMMA at Daresbury o Design carbon therapy NS-FFAG and prototype o Seek funds to build prototype - 2 rounds; “highly ranked” in 1st - 2nd round: submitted 27th July - Results mid-November - Funding ~ start early 2007 - 1st beam before end 2009

48. FFAGs in the UK • Tracking studies: -EMMA - Proton driver NS-FFAG - Carbon therapy NS-FFAG (just starting) 10 GeV non-scaling FFAG n=5, h=40, radius = twice booster radius = 127.576 m 3 GeV RCS booster mean radius = 63.788 m Proton driver for a Neutrino Factory E-model “planned” to follow EMMA at DL n=5, h=5 180 MeV Hˉ linac Achromatic Hˉ collimation line

49. EMMA –kicker design

50. Summary: • - Newest developments in the Fixed Field Alternating Gradient [FFAG] designs and new • accelerators commissioning project have been presented. • - The new 150 MeV scaling FFAG at KEK, Japan has been commissioned, while similar • scaling FFAG accelerator complex in Kyoto is very close to commissioning. • - There are also spiral scaling FFAG designed and one is commissioned at Kyoto • University as well proposed for the upgrade of the proton-driven experiment • - There are few projects in progress in non-scaling FFAG all connected to the same • goal of making a demonstration electron model ring. In USA there are three SBIR • (Small Business Innovation Research) fully funded by the DOE ($150k I phase, $300k II, • and higher for the third phase – contact person D. Trbojevic), EMMA in UK (Rob Edgecock), • RASCAM – Grenoble France, EUROFFAG (Francois Meot). • A conceptual problem of FFAG acceleration for protons or heavy ions has been resolved by • the “harmonic number jump” by S. Ruggiero. [Kolomenski, 1953]. • A new beam line was designed for the carbon/proton therapy facilities, by using the • same principle of the non-scaling FFAG trying to reduce the large magnet size of the gantries. • FFAG designs to accelerate carbon/proton ions for medical applications, heavy ions for RIA, • electrons for eRHIC or electron models, muons for neutrino factory or future muon-collider, • etc., have been demonstrated. • A race track non-scaling FFAG ahs been designed to accelerate muons.