Presentation on theme: "PAMELA – A Novel Accelerator for Charged Particle Therapy"— Presentation transcript:
1 PAMELA – A Novel Accelerator for Charged Particle Therapy H WitteJohn Adams Institute for Accelerator Science, Keble Road, Oxford, OX1 3RH, UK
2 Development status and technological challenges OverviewMotivationCancer treatmentThe situation in the UKPAMELAGeneral conceptDevelopment status and technological challengesMain accelerator magnets: Helical CoilsExtractionSummary
4 Incidence of Cancer in the UK Source: Cancer Research UK12.5% probability, all types (except skin cancer) by 65Rises to more than 1/3rd for whole-lifeAround half are associated with specific risks
5 Motivation Radiation treatment is very effective Cancer treatment [Statistics show that of those cured...] “49% are cured by surgery,40% by radiotherapy and11% by chemotherapy”. The Royal College of Radiologists, BFCO(03)3, (2003).Cancer treatmentIn 40-50% of all cases radiotherapy is part of the treatment planMotivation for protons and light ions: most of energy deposited in Bragg peak
6 Medulloblastoma in a child With ProtonsWith X-rays10060101006010“When proton therapy facilities become available it will become malpractice not to use them for children [with cancer].”Herman Suit, M.D., D.Phil.Chair, Radiation MedicineMassachusetts General Hospital
9 PAMELAParticle Accelerator for Medical Applications
10 CONFORMThe COnstruction of a Non-scaling FFAG for Oncology, Research and MedicineEMMA (Electron Model with Many Applications)PAMELAApplicationsLook for other applications of ns-FFAGsHistoryStart: September 2005; PPARC KITE Club MeetingOctober 2005, Radiation, Oncology & Biology Department, OxfordAgreed to bid for EMMA and PAMELA to Basic Technology FundApril 4th 2006: Bid submittedNovember 8th 2006; Basic Technology Panel meetingAwarded in full £8.5M
16 Working Point and Tunes Choose high k to minimize orbit excursionReasonably far away from instability regionTotal machine tune variation (cell tune variation*12):νx within 0.1νy within 0.24Well within an integer!Beam blow upLinear lattice: Amplification factor 360Non-linear lattice: 7.6(A = orbit distortion [mm] / 1σ alignment error [mm])Achievable alignment toleranceSuzy Sheehy et al. PRST-AB.
17 Carbon Ring Carbon ring Same concept Radius: 9.3 m k = 42 68 to 400 MeV/uSame conceptRadius: 9.3 mk = 42Magnet length: 1.14 mProtons: <0.56 m18.6 mPacking FactorNo. cellsRadiusOrbit ExcursionStraight Section0.65129.3 m0.246 m1.2 mShinji Machida, Suzy Sheehy, Takeichiro Yokoi
19 Requirements Non-scaling, non-linear FFAG Challenges Consider multipoles up to octupoleChallengesMaximum field (4.25T)Required bore (>250 mm)Length restrictionHigh kApproach: Double-helix coilsKnown since the 70s
21 Double-Helix: Combined Function Magnets Advantage: tuningDisadvantage: heat leak...
22 ‘True’ Combined Function Magnets Generalization‘mixing factor’ εnAdvantagesOne coil with same currentCryogenic advantagesDisadvantagesMP hardwired – trim coils necessary
23 Proton Ring Radius former 140 mm Length: 535 mm Outer radius: 209.2 mm J = A/mm2Temperature margin: 2K32 layersTrim coils: Individual helical coilsR= mmTunabilityDipole: 1%Quadrupole: 4%Sextapole: 6%Octapole: 9%Cu:Sc ratio of 1.35:1Ic: 1084A at 7T1.681.091.791.17
27 Double-Helix Coils Vertical field as expected Horizontal field perturbedWhy?Helical coil: solenoidal field + useful fieldSolenoidal field should cancel outStray field: uncompensated solenoidal field
28 Solenoidal Field Solenoids Radius for coils is never the same B depends on current (fixed) and radiusRadius for coils is never the sameAlways small difference in fieldQuadruple helixAllows compensationDouble Helix (2 times)Quadruple Helix
29 Double/Quadruple Helical Coils Quadruple helix: two nested double-helix coils, which compensate solenoidal field
31 Tracking – Double-helix vs. Quadruple Helix S. Sheehy and H. Witte
32 ZGOUBI – Double-helix vs. Quadruple Helix NumericalnoiseS. Sheehy and H. Witte
33 Quadruple Helix – Phase Space Quadruple helix concept filed for patent in November 2009Patent GBISIS Innovation, Oxford University
34 3D Field Map Tracking - Stable Tunes After optimization: Tune change within 0.3/0.27 (machine)Patent pending...Horizontal tuneVertical tuneBρ
35 Helical Coil vs. Classical Designs Consider classical dipoleTwo main differencesAutomatically more sectionsMore cross-sectional area coveredNot blocks of constant current densityEffectBetter field qualityLess steep gradients of vector potentialLower magnetic field on wireCoupland. NIM (78):181-4, 1970.
51 Summary and Outlook PAMELA R&D Ongoing work Exciting project to introduce CPT to the UKR&DMany issues have been solved (on paper...)Lattice, RF, injector and kicker magnetsMagnetsHelical coils are fascinating alternativeVery good field quality, better performanceVery flexibleOngoing workGantryTransport line4T septumPAMELA is not the only interesting developmentRCS, Cyclinacs, IBA C400, Still River, ...Future should be very exciting!