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R&D Status of cancer therapy accelerator PAMELA. Takeichiro Yokoi. FFAG ( Fi xed F ield A lternating G radient) Accelerator has the ability of rapid particle acceleration with large beam acceptance. wide varieties of applications.
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R&D Status of cancer therapy accelerator PAMELA Takeichiro Yokoi Accelerator for cancer therapy By T.Yokoi
FFAG (Fixed Field Alternating Gradient) Accelerator has the ability of rapid particle acceleration with large beam acceptance. wide varieties of applications Introduction ... EMMA Particle therapy Particle physics Medical -factory, muon source, proton driver PAMELA FFAG Particle therapy, BNCT, X-ray source ADSR FFAG Energy (PAMELA) FFAG ADSR, Nucl. Transmutation -factory CONFORM (Construction of a Non-scaling FFAG for Oncology, Research and Medicine)aims to develop the Non-scaling FFAG as a versatile accelerator. (Project HP: www.conform.ac.uk) Accelerator for cancer therapy By T.Yokoi
3.5 years project (Apr. 2007~) with total funds £6.9m from STFC/EPSRC Basic Technology Fund (UK government) CONFORM: project overview • 3 parts of the project are funded • EMMA : Construction of electron NS-FFAG as a scaled down model of muon accelerator for neutrino factory • PAMELA : Design of proton and HI accelerator for particle therapy using NS-FFAG • (other Applications) : ex ADSR (THoreA) Project manager : K.Peach (JAI, Oxford university) UK based : Birmingham University Brunel Utility Cockcroft Institute Daresbury Laboratory Gray Cancer Institute Imperial College London John Adams Institute Manchester University Oxford University Rutherford Appleton Laboratory Project manager : K.Peach (JAI, Oxford university) UK based : Birmingham University Brunel University Cockcroft Institute Daresbury Laboratory Gray Cancer Institute Imperial College London John Adams Institute Manchester University Oxford University Rutherford Appleton Laboratory International CERN FNAL (US) LPNS (FR) TRIUMF (CA) International CERN FNAL (US) LPNS (FR) TRIUMF (CA) J.Cobb K. Peach S.Sheehy T.Witte T.Yokoi J.Cobb K.Peach S.Sheehy H.Witte T.Yokoi • 3 parts of the project are funded • EMMA : Construction of electron NS-FFAG as a scaled down model of muon accelerator for neutrino factory • PAMELA : Design of proton and HI accelerator for particle therapy using NS-FFAG • (other Applications) : ex ADSR (THoreA) Accelerator for cancer therapy By T.Yokoi
Scaling FFAG to NS-FFAG In fixed field accelerator (FFAG, cyclotron)….. Easiness of control Hardness of commissioning and tuning In fixed field accelerator (FFAG, cyclotron)….. Ease of control Difficulty of commissioning and tuning All FFAGs so far built are designed to form scaling magnetic field Hard to change operating point after construction KEK 150MeV FFAG In PAMELA, each multipole field up to decapole can be tuned individually. Flexible tunability of operating point. “Separated function FFAG” Accelerator for cancer therapy By T.Yokoi
PAMELA:Particle Acceleratorfor MEdicaL Applications Spot scanning FFAG Integrated current Step size controls dose time “Digital IM” Beam intensity is modulated depth-wise proton photon From PSI website • Advantage of particle therapy ( X-ray) • (1) better dose concentration • (2) better biological effectiveness • PAMELA : design study of particle therapy facility using NS-FFAG Prototype of versatile FFAG (ex ADSR) • Advantage of NS-FFAG as particle therapy accelerator • (1) High intensity(synchrotron) • (2) Flexible machine operation (cyclotron) • Spot scanning with proton and carbon beam is aimed to realize in PAMELA (better conformal dose field). • IMPT (Intensity Modulated Particle therapy) requires high repetition rate Accelerator for cancer therapy By T.Yokoi
PAMELA: ring overview Injector(c): RFQ+LINAC Injector(p): cyclotron Proron ring Carbon ring • Long straight section (~1.3m) • Small beam excursion (<20cm) • Strong field (max 4T) SC magnet • High repetition rate (~1kHz) is a big challenge Accelerator for cancer therapy By T.Yokoi
2009 Upward crossing Horizontal B/B0=(r/r0)k Horizontal@injection Vertical Downward crossing 2008 PPR RD/F(B·l)D/ (B·l)F F Vertical@injection D S.Sheehy F By S.Sheehy Beam dynamics Challenges: compatibility of stable tune and operational flexibility • Tune stablization was achieved (∆H<0.1, ∆H<0.05) no need to worry about resonance crossing • Tune can be varied over |∆|<0.25 • Relation with field quality and tune drift was well studied • Know-how to tailor tune drift was obtained • Dynamic aperture is sufficiently large for proton accelerator (>400 mm mrad) Understanding of beam dynamics is steadily going forward Accelerator for cancer therapy By T.Yokoi
Magnet Dipole Superposition of helical field can form multipole field SC magnet module 55cm Quadrupole ~23cm Dipole • Unknowns ….. • Alignment scheme • Positioning error …. • Local field interference Prototyping is required !! • Unknowns ….. • Mechanical accuracy ex positioning error coil winding Prototyping is required Octapole Sextapole Challenges: Large aperture, short length, strong field • Tunability of Individual multipole flexible operation • Improved coil configuration (Patent was recently filed) By H.Witte Accelerator for cancer therapy By T.Yokoi
Beam extraction ∆x>2cm @kicker Septum Kicker Septum Kicker CO @septum FDF FDF 230MeV (Bkicker:0.6kgauss) Kicker field (proton) Septum field (proton) By H.Witte Challenges: Energy variable extraction in fixed field accelerator Large horizontal beam excursion (ex PAMELA: ~10cm (70MeV230MeV) Vertical fast extraction was adopted in PAMELA Advantages: (1) weaker kicker field, (max 0.6kgauss1m for proton ) (2) good matching with FFAG transport Hardware R&D of kicker is under planning (budget request) Specifications of kicker and septum are within feasible range of engineering for proton. Accelerator for cancer therapy By T.Yokoi
RF system 2 ferrite core layers • Unknowns ….. • Ferrite Properties (ex Q-value, high loss effect, dynamic loss effect • Phase error • Unknowns ….. • Ferrite Properties (ex Q-value, high loss effect, dynamic loss effect • Phase error 1.1m Ferrite sample Challenge : high duty cycle, high rate FM, high field gradient Power dissipation is the most serious problem in high repetition operation P=V2/(2QL) Higher Q is favorable One solution : Ferrite loaded cavity * tuning bias current is required * 1KHz repetition rate is 10 times larger than that of existing ferrite rf cavity Ferrite property measurement has started Accelerator for cancer therapy By T.Yokoi
Upgrade options ( to carbon ring) Real challenges are extraction and acceleration In carbon ring, Z/A=2, max rigidity : 2.6 Real challenges are extraction and acceleration carbon(A/Z=2): hard to bend, accelerate Downward crossing Septum structure ESS Option2 Option 1 Energy Energy Carbon, k=42 H Resonance point ESS Packing factor Ldrift > 1.2m Multi-bunch painting time time Hori. field Bmax <3.5T v Max bore <35cm PRISM rf cavity “With Flattop” E + Wave superposition R0 [m] ∆RD/F :0.017 Direct IM t Hori. field quality = Option 1: P Nrep2 ∆v=0.5 Option 2: P Nrep Active chopper By S. Sheehy For carbon ring, (doable) lattice was proposed. Extraction resonance extraction • unique feature of PAMELA. • extraction kicker can be eliminated (1)’ Extraction SC septum • HTS shield for stray field suppression (2) Acceleration multi-bunch acceleration • potentially, more efficient than ferrite cavity • well-matched with resonance extraction (3) Intensity modulation(IM) Direct IM • IM@ion source +Active chopper • enhance effective repetition rate Versatile technologies for high intensity accelerator (ex ADSR) Accelerator for cancer therapy By T.Yokoi
R&D plan and resources Resource request test bench + support from CE( rf development ) 1 FTE Resource request test bench + support from CE( rf development ) 1 FTE By end of 2009, Overall ring design is to be finished ( July 2009, PAMELA design review) Budget request for hardware R&D Magnet : fabrication process, field distribution, field quality etc Kicker : wide-aperture kicker, life time etc RF system :ferrite property, dynamic loss effect etc. Proposal for full size machine (+facility) construction Collaboration with MPRG Collaboration with nuclear engineering and particle physics (proton driver, ADSR etc) Accelerator for cancer therapy By T.Yokoi
2009 PP project review (1) Lattice Stable lattice (∆<0.1) **no resonance crossing tune control scheme : fixed (2) Magnet R&D work :started, patent :filed (3) RF Scheme:Fixed, R&D work: started (4) Extraction Scheme: Fixed R&D work: started (5) Extension to Carbon ring lattice : propose (6) Misc Resonance extraction, multi-bunch acceleration, direct intensity modulation etc… 2009 PP project review (1) Lattice Stable lattice (∆<0.1) **no resonance crossing tune control scheme : fixed (2) Magnet R&D work :started, Improved winding (patent:filed) (3) RF Scheme:fixed, R&D work: started (4) Extraction Scheme: fixed R&D work: started (5) Extension to Carbon ring lattice : proposed (6) Misc Resonance extraction, multi-bunch acceleration, direct intensity modulation etc… Progress from 2008 to 2009 2008 PP project review (1) Lattice Scheme fixed (∆>0.5**) ** resonance crossing is must (2) Magnet Scheme : fixed (3) RF Options: listed up (4) Extraction Scheme : proposed (5) Extension to Carbon ring ?? 2008 PP project review (1) Lattice Scheme fixed (∆>0.5**) ** resonance crossing is must (2) Magnet Scheme : fixed (3) RF Options: listed up (4) Extraction Scheme : proposed (5) Extension to Carbon ring ?? We are creeping forward to the goal !! Accelerator for cancer therapy By T.Yokoi