Carbon therapy machine Working group2 FFAG workshop 2003 at KEK
Target specification of the beam for carbon therapy Beam species C6+ E = 80 – 400MeV/u = 1 x 6 nA Repetition rate 120Hz(240Hz)
Schematic diagram of the system ion source booster main ring RFQDTL 62MeV/u C6+ 230MeV proton 400MeV/u C6+ 1.2GeV proton proton therapy carbon therapy proton driver? 0.75MeV/u C MeV/u C6+ 7MeV proton
Plasma Target Chamber RFQ Slit 4mm Insulator (MC nylon) C Target (Rotateable) Na Cl Laser Beam Properties of the laser plasma Energy of the ions : about 100 eV/u Emission angle : less than ±20 degrees Lens Focal Spot Size on Target Surface: d = 1.22f l/D = 64.7 m Power Density: P = W/(p(d/2) 2 ) W/cm 2 H. V.
Photo album of the experiment (Okamura RIKEN)
Beam Spec at the end of injector 1s1s 120Hz E=1.75MeV/u 1E9 ppp = 115nA N =1pmm-mrad
Booster (radial sector) Energy B Ncell k Bmax tune Long straight r excursion 1.75 – 62MeV/u 0.38 – 2.32Tm T (4.2,1.4) 0.75m – 5.000m 0.647m
Lattice functions of the booster ring ( radial sector)
Booster (spiral sector) Ncell k f pack Bmax tune Long straight r excursion degree 1.66T (4.4, 1.3) 1.36m – 4.000m 0.517m
Lattice functions of the booster ring ( spiral sector)
Radial or Spiral Machine parameters tell spiral sector ring preferable. For medical use, extraction energy from the main ring should be able to changed MeV/u. Booster should be able to change k value. Can we change k in spiral lattice?
Tunability of k in a spiral booster
Main ring(spiral) E B Cirumference Ncell k f pack Bmax tune Long straight r excursion MeV/u 2.32 – 6.35Tm 45m degree 1.97T (3.9, 1.3) 1.55m 6.62 – 7.16m 0.533m
Lattice functions of the main ring
Injection and extraction scheme booster main ring Injector 1 turn injection fast extraction 1 turn injection massless extraction
Frequency0.84MHz ～ 4.15MHz Acc. voltage11.0kV （ φ ＝ 60° ） # of cavities2 Core thickness30mm # of cores3/cavity 410mm Booster(spiral) ring rf cavity parameters
Booster ring core shape Shunt impedance151Ω/cavity RF power25kW/cavity Core weight310kg/core
Main ring rf cavity parameters Frequency6.62MHz ～ 7.15MHz Acc. voltage16.0kV （ φ ＝ 60° ） # of cavities2 Core thickness30mm # of cores3/cavity 410mm
Main ring core shape Shunt impedance118.4Ω/cavity RF power100kW/cavity Core weight~274kg/core
Power consumption Preinjector350kW Boostermagnet280kW cavity50kW Main ringmagnet800kW cavity200kW total1680kW
Summary Preliminary parameters of the carbon therapy system have been obtained. Spiral sector lattice seems to be ok for the main ring and the booster considering optics and geometrical configuration. The main ring is very compact comparing to existing carbon machines. C=45m The booster ring can be used as proton therapy machine.
Stability of the spiral lattice. Optimization of operating point Precise beam tracking simulation using TOSCA’s data. Injection / extraction calculation. Synchronization between the booster and the main ring Hardware feasibility study - Injection/extraction kicker magnets and their power supplies - How to realize 2.0T B field in the main ring - Pole-face winding method - etc Things to do