Carbon therapy machine

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Carbon therapy machine

• Working group2
• FFAG workshop 2003 at KEK

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Target specification of the beam for carbon
therapy

• Beam species C6
• E 80 400MeV/u
• ltIgt 1 x 6 nA
• Repetition rate 120Hz(240Hz)

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Schematic diagram of the system
proton therapy
carbon therapy proton driver?
ion source
RFQ
DTL
booster
main ring
0.75MeV/u C6
1.75MeV/u C6 7MeV proton
62MeV/u C6 230MeV proton
400MeV/u C6 1.2GeV proton
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Plasma Target Chamber
Insulator (MC nylon)
C Target (Rotateable)
Focal Spot Size on Target Surface d 1.22f l/D
64.7 mm
RFQ
Laser Beam
Power Density P W/(p(d/2)2) 3.35 1012 W/cm2
Na Cl
H. V.
Lens
Slit 4mm
Properties of the laser plasma Energy of the ions
about 100 eV/u Emission angle less than 20
degrees
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Photo album of the experiment (Okamura RIKEN)
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Beam Spec at the end of injector
E1.75MeV/u 1E9 ppp ltIgt 115nA eN1pmm-mrad
1ms
120Hz
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Booster (radial sector)
Energy Br Ncell k Bmax tune Long
straight r excursion
1.75 62MeV/u 0.38 2.32Tm 12 12 2.0T (4.2,1.4)
0.75m 4.353 5.000m 0.647m
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Lattice functions of the booster ring ( radial
sector)
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Booster (spiral sector)
Ncell k fpack z Bmax tune Long straight r excursio
n
12 12 0.35 57 degree 1.66T (4.4, 1.3) 1.36m 3.483
4.000m 0.517m
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Lattice functions of the booster ring ( spiral
sector)
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Radial or Spiral

• Machine parameters tell spiral sector ring
  preferable.
• For medical use, extraction energy from the main
  ring should be able to changed 70-400MeV/u.
• Booster should be able to change k value.
• Can we change k in spiral lattice?

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Tunability of k in a spiral booster
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Main ring(spiral)
E Br Cirumference Ncell k fpack z Bmax tune Long
straight r excursion
62 - 400MeV/u 2.32 6.35Tm 45m 16 12 0.45 64
degree 1.97T (3.9, 1.3) 1.55m 6.62 7.16m 0.533m
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Lattice functions of the main ring
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Injection and extraction scheme
Injector
1 turn injection
booster
1 turn injection
fast extraction
massless extraction
main ring
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Booster(spiral) ring rf cavity parameters
Frequency 0.84MHz4.15MHz Acc. voltage 11.0kV
(f60) of cavities 2 Core thickness 30mm
of cores 3/cavity
410mm
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Booster ring core shape
Shunt impedance 151O/cavity RF
power 25kW/cavity Core weight 310kg/core
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Main ring rf cavity parameters
Frequency 6.62MHz7.15MHz Acc. voltage 16.0kV
(f60) of cavities 2 Core thickness 30mm
of cores 3/cavity
410mm
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Main ring core shape
Shunt impedance 118.4O/cavity RF
power 100kW/cavity Core weight 274kg/core
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Power consumption
Preinjector 350kW Booster magnet 280kW cavity
50kW Main ring magnet 800kW cavity 200kW tot
al 1680kW
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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. C45m
• The booster ring can be used as proton therapy
  machine.

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Things to do

• Stability of the spiral lattice.
• Optimization of operating point
• Precise beam tracking simulation using TOSCAs
  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