April ERICE11 Status of PAMELA Status of PAMELA an overview of particle therapy facility using NS-FFAG PAMELA collaboration Brunel University Cockcroft Institute Daresbury Laboratory Gray Cancer Institute Imperial College, London John Adams Institute, Oxford Univ. Manchester University Oxford University Particle Therapy Cancer Research Inst., Oxford Univ. Rutherford Appleton Laboratory CERN FNAL (US) LPNS (FR) TRIUMF(CA) April ERICE11 Status of PAMELA Contents Overview of CONFORM & PAMELA PAMELA design Medical requirement Lattice Magnet RF Injection & Extraction Transport & Gantry April ERICE11 Status of PAMELA Particle physics -factory, muon source, proton driver -factory -factory FFAG Medical Particle therapy, BNCT, X-ray source Particle therapy FFAG Energy ADSR, Nucl. Transmutation ADSR FFAG FFAG(Fixed Field Alternating Gradient) Accelerator has an ability of rapid particle acceleration with large beam acceptance. wide varieties of applications CONFORM ( 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:EMMA PAMELA (PAMELA) Introduction... April ERICE11 Status of PAMELA CONFORM: Project Overview 3.5 years project(Apr. 2007~) with total funds 6.9m from STFC (UK government). Now finishing 3 parts to the project are funded 1. EMMA : Construction of electron NS-FFAG as a scale down model of muon accelerator for neutrino factory 2. PAMELA : Design of proton and HI accelerator for particle therapy using NS-FFAG 3. (other Applications) : ex ADSR (THoreA) International Collaboration (UK, EU, US, Canada etc) April ERICE11 Status of PAMELA PAMELA: overview PAMELA (Particle Accelerator for MEdicaL Application) aims to design a particle therapy facility using NS- FFAG 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. It aims to provide spot scanning with proton and carbon beam. 2 cascaded rings (For proton, 1st ring is used. For carbon, 1st ring is used as a booster) 2 cascaded rings (For proton, 1st ring is used. For carbon, 1st ring is used as a booster) Flexible change of beam energy and particle is required Flexible change of beam energy and particle is required Extracted beam : pulsed beam high repetition rate is required for active beam scanning Extracted beam : pulsed beam high repetition rate is required for active beam scanning Particlep,C Ext Energy:p (MeV)70~250 (variable) Ext Energy:C(MeV/u)110~450 (variable) Repetition rate(KHz)0.5~1 Voxel size (mm) 4 4~10 10 Active beam scanningSpot scanning Switching time:p c(s) 1kHz) and optimization of bunch intensity granularity are crucially important for efficient treatment with pulsed accelerator April ERICE11 Status of PAMELA Even with multi-bunch painting scheme, intensity modulation of more than factor of 30 would be required for efficient spot scanning with pulsed beam. Intensity control at injector is a requirement Dynamic range of intensity modulation One-time dose in proton therapy at Tsukuba univ. proton therapy centre (By courtesy of T.Okumura, Tsukuba univ) Low radiosensitive tissue (lung, liver etc) high radiosensitive tissue (brain, perif. of digestive canal etc) In real treatment, single prescribed dose varies more than factor of 7. **multi-field irradiation is assumed (numerical study using treatment planning system is under going ) Even with multi-bunch painting scheme, intensity modulation of more than factor of 30 would be required for efficient spot scanning with pulsed beam** Intensity control at injector is a requirement April ERICE11 Status of PAMELA Efficiency of multi-bunch painting In ideal situation, multi-bunch painting is about factor of 10 less efficient compared to dynamic intensity modulation. However, in real beam scanning, beam position has an inevitable systematic deviation from ideal position systematic dose field non-uniformity is incurred Grid size : 5mm, Beam size : 5mm ( ) Ideal case: x:0mm( ) x:0.3mm( ) D/D: 1 D/D: 4 Beam positioning error vs maximum dose field error ( Beam positioning error vs maximum dose field error (Grid size : 5mm, Beam size: 5mm( ) 10cm 10cm field, 100 random samples) April ERICE11 Status of PAMELA Efficiency of multi-bunch painting Rescanning can improve the uniformity caused by the beam position error, but only proportional to Rescanning can improve the uniformity caused by the beam position error, but only proportional to To achieve the overall uniformity for most case, required number of rescanning increases drastically as the beam positioning error gets worse To achieve the overall uniformity for most case, required number of rescanning increases drastically as the beam positioning error gets worse Even the best case ( x:0.2mm( ) ), rescanning more than 5 times would be needed. Even the best case ( x:0.2mm( ) ), rescanning more than 5 times would be needed. Multi-beam painting is in itself rescanning, if beam spot moves bunch by bunch. Multi-beam painting is in itself rescanning, if beam spot moves bunch by bunch. In the case of rescanning, efficiency of multi- bunch painting and that of dynamic intensity modulation are almost similar (For multi-bunch painting, combination with active chopping will provide further improvement of efficiency In the case of rescanning, efficiency of multi- bunch painting and that of dynamic intensity modulation are almost similar (For multi-bunch painting, combination with active chopping will provide further improvement of efficiency Number of rescanning vs. maximum Dose field ( 5mm grid, 100sample, size 5mm, ) Number of rescanning vs. maximum Dose field ( 5mm grid, 100sample, size 5mm, x:0.2mm( ) ) Minimum number of rescanning vs. beam position error to ensure 2% tolerance for 99% case April ERICE11 Status of PAMELA Acceleration rate of ordinary synchrotron is limited by the ramping speed of magnet (magnet PS :V=LdI/dt, eddy loss: rot E+dB/dt=0) Scaling FFAG realizes stable betatron tune by non-linear field B/B 0 =(r/r 0 ) k f( ) Radial sector Spiral sector What is Scaling FFAG ? Acceleration rate of ordinary synchrotron is limited by the ramping speed of magnet (magnet PS :V=LdI/dt, eddy loss: rot E+dB/dt=0) Acceleration rate of fixed field accelerator is limited by acceleration scheme (in principle, no limitation) ~1.2m KEK 150MeV FFAG It requires large excursion combined function magnet p/p 0 =(r/r 0 ) k+1 It can accelerate large emittance beam with high repetition rate (ex KEK PoP FFAG:1ms acceleration, 5000 mmmrad) KEK 150MeV FFAG 100Hz extraction April ERICE11 Status of PAMELA PAMELA : Lattice =simplification based on scaling FFAG(triplet FDF) Step 1. Truncated multipole field Tune drift width depends on included orders 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 April ERICE11 Status of PAMELA Cell layout April ERICE11 Status of PAMELA PAMELA Rings Ring #1 (p, c)Ring #2 (c) Energy30~250MeV (p) 8~68MeV/u (c) 68~400MeV/u # of Cell12 Diameter12.5m18.4m K-value3841 Orbit excursion18cm21cm Rev. freq1.94~4.62MHz(p) 0.98~2.69MHz(c) 1.92~3.91MHz MagnetTriplet(FDF), SC length57cm113cm aperture25cm33cm Long Drift1.3m1.2m Packing factor Inj./Ext1turn inj/ext 2 LD (each) 1turn inj/ext 2 LD (each RFMax 8 LD Stable betatron tune