1. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Status of PAMELA Takeichiro Yokoi(JAI)

2. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA: overview PAMELA (Particle Accelerator for MEdicaL Application) aims to design a particle therapy facility using NS-FFAG It aims to provide spot scanning with proton and carbon beam. 2 cascaded ring (for proton, only 1st ring is used, for carbon, 1st ring is booster) on going R&D Items 1. Injector 2. Proton ring, Carbon ring 3. Transport 4. (Gantry) Particlep,C Ext Energy:p (MeV)60~240 Ext Energy:C(MeV/u)110~450 Dose rate (Gy/min)>2 Repetition rate(KHz)0.5~1 Bunch charge:p(pC)1.6~16 Bunch charge;C(fC)300~3000 Voxel size (mm) 4  4  4~10  10  10 Spot scanning Switching time:p  c(s) <1 # of ring2 (*2nd ring :for C)

3. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Clinical requirements : IMPT Dose uniformity should be < ~2%  Shape of Bragg peak requires to modulate beam intensity delivered to each voxel IMPT (Intensity Modulated Particle Therapy) More than one order magnitude of intensity modulation is required for spot scanning

4. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Clinical requirements : IMPT time Integrated current Synchrotron & cyclotron Gate width controls dose “Analog IM” time Integrated current FFAG Step size controls dose “Digital IM” With pulsed beam of FFAG, to realize intensity modulation ….. (1) Dynamic modulation of injector beam intensity complicated system, but low repetition rate (2) multi-beam painting with small bunch intensity simple system, but high repetition rate In PAMELA, option (2) was taken, due to the injector scheme and uncertainty about precision of intensity modulation of ion source

5. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA : Lattice =simplification based on scaling FFAG(triplet FDF) Step 1. Truncated multipole field Tune drift width depends on included order of multipole field (in PAMELA, up to decapole) Step 2. Sector magnet  rectangular magnet Step 3. Magnet is linearly aligned (* scaling FFAG is co-centric) F FF F D D By S.Machida (RAL)

6. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA 30cm 55cm 6.6cm

7. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA : Magnet Superposition of helical field can form multipole field Challenges: Large aperture, short length, strong field Dipole Quadrupole Octapole Sectapole ~23cm 55cm Applicable to superconducting magnet Each multipole can be varied independently  Operational flexibility Present lattice parameters are within engineering limit By H.Witte (JAI)

8. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA : Magnet Dipole Field quality of all the field components are well controlled (∆B i /B i (i =0~4) <1  10 -3 ) Now, 3D field is being included into tracking code By H.Witte (JAI)

9. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA Lattice : Choice of operating point PAMELA uses large-k region to reduce orbit excursion (  H >0.5) p/p 0 =(r/r 0 ) k+1 Stable operating region of scaling FFAG(triplet configuration) Usually small - k region is used (  H <0.5) Field index :k D/F 0 -0.5 -1.5 -2 20 100 40 60 80 F F D

10. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA lattice (proton ring) Stable betatron tune ∆ <1 Long straight section (~1.7m) Small beam excursion(<20cm) Strong field (max 5T) : SC magnet is a requirement Simple manget configuration (FDF triplet, truncated multipole, rectangular combined function magnet, linearly aligned ) 12.5m 1.7m Energy30~250MeV (for p) 8~70MeV/u (for C) # of Cell12 Radius6.25m Orbit excursion18cm Rev frequency1.94~4.62MHz MagnetTriplet(FDF),SC Magnet length31cm Magnet aperture25cm Max field5T Straight section1.7m Packing factor0.48 Injection/extraction1turn inj/ext 2 straight section(each) RFMax 8 straight section

11. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA lattice Operating point (k=38) Vertical tune :high Tune drift of present lattice: ∆ H <0.1, ∆ v <0.05  No Need to worry resonance crossing * Tracking is carried out using ZGOUBI (developed by F. Meot) By S.Sheehy (JAI)

12. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA lattice : tune control We are getting a know-how to control tune drift … Decapole control the gradient of tune drift Octapole control the curve of tune drift ∆B Deca : -0.4 ∆B Deca : 0.4 ∆B octa : -0.2, B deca :0 ∆B octa : 0 ∆B Deca : 0

13. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA lattice :tune control Knobs of tune control in PAMELA Overall tune  k-value, D/F Overall tune  k-value, D/F Tune drift Tune drift gradient  decapole gradient  decapole curve  octapole curve  octapole ` Present PAMELA magnet scheme can change each multipole component independently  It provides FFAG a large flexibility of tune adjustment which fits its application.

14. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi PAMELA lattice : Dynamic aperture Horizontal Vertical By S.Sheehy

15. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Injector Injector can preferably cope with proton and heavy ion injection   Two injectors are to be employed: cyclotron for proton, RFQ for HI   Typical beam emittance from injectors : 1  mm mrad (normalized)   Tracking study of RFQ line is undergoing. (transmission efficiency> 99% is achieved   Stability of intensity is typically less than 5% By J.Pozimski, M.Easton By J.Pozimski, M.Easton

16. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Beam extraction Challenges: Energy variable extraction in fixed field accelerator ∆R  11cm Horizontal extraction requires orbit separation of more than 13cm for energy variable extraction in PAMELA The difficulties are …. (1) Large horizontal aperture has large inductance : L=  0 (w·l)/g   The difficulties are …. (1) Large horizontal aperture has large inductance : L=  0 (w·l)/g  voltage of kicker PS is unrealistic (2) Non-linear field prevent making large orbit separation (max ∆r  9cm) (3) How to match the orbit with transport line Horizontal extraction was given up in PAMELA Kicker Septum Kicker Septum Required field : 0.29T.m

17. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Beam extraction FDF Kicker#1 Septum @kicker CO @septum 230MeV (B kicker :0.6kgauss) Vertical extraction was adopted in PAMELA Advantages: (1) weaker field,(max 0.6kgauss  1m) (2) good matching with FFAG transport, (3) extraction kicker can be used as injection kicker ∆x>2cm Problems: (1) Uncertainty of inductance (aperture g:19cm,w:3cm,l:100cm) (2) Uncertainty of fringing field (*vertical dynamics is sensitive to fringing field  3D field tracking is crucially important) (3) Capacity of PS(I>8000A) Hardware R&D of kicker is under planning (budget request)

18. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Beam transport Challenge : beam transport with large momentum acceptance One solution : (scaling) FFAG transport For the magnet for the transport, helical coil magnet can be used By S. Machida (RAL)

19. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi FFAG Beam transport Intensive tracking study is under going now. By S. Machida(RAL), R.Fenning (Brunnel univ.)

20. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi RF system Requirement : 1kHz repetition rate  100kV/turn Available space : 6 drift space  1.2m (L drift ~1.7m) Requirement : 1kHz repetition  100kV/turn Available space : 8 drift space  1.2m (L drift ~1.7m) Target energy gain: 15kV/turn/cavity Challenge : high duty cycle, high rate FM, high field gradient One solution : Ferrite loaded cavity * tuning with bias current is required Relatively high Q (~100) h=10  power consumption is~100kW/cavity P=V 2 /(4  fQL) Power dissipation is the most serious problem in high repetition operation Higher Q is favorable 1.1m 2 ferrite core layers Energy gain 15keV/turn Frequency(h=1)1.94~4.62MHz Length1.1m Aperture23cm Repetition rate1kHz Power/cavity~100kW By I. Gardner (RAL)

21. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi RF system Development has just started Step 1: Ferrite property measurement Step 2: Prototyping (budget request is needed) Q-value FM rate dependence (dynamic loss effect) Power dissipation Power density dependence (high loss effect) Phase error problem PAMELA rf system operated with high power, high frequency modulation rate needs to consider ….. (1) Dynamic loss effect (2) High loss effect (3) Phase error

22. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi R&D schedule By end of 2009, Overall ring design is to be proposed Proposal for full size machine construction Budget request for hardware R&D Budget request for hardware R&D 1.Magnet : fabrication process, field distribution, field quality etc 2.Kicker : wide-aperture kicker, life time etc 3.RF system :ferrite property, dynamic loss effect etc.

23. ADSR meeting@ Cockcroft ins., 10,July, 2009 Status of PAMELA, T.Yokoi Summary PAMELA intends to design particle therapy facility to deliver proton and carbon using NS-FFAG. 1kH is the target repetition rate Intensive study is going on (dynamics, rf, magnet, clinical requirement etc.)  By the end of this year, an doable overall scenario is planned to be proposed.  Hardware R&D proposals will be followed