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

• <I> = 1 x 6 nA

• Repetition rate 120Hz(240Hz)

Schematic diagram of the system

ion source

boostermain ring

RFQ DTL

62MeV/u C6+

230MeV proton400MeV/u C6+

1.2GeV proton

proton therapycarbon therapy

proton driver?

0.75MeV/u C6+

1.75MeV/u C6+

7MeV proton

Plasma Target Chamber

RFQ

Slit 4mm

Insulator(MC nylon)

C Target(Rotateable)

Na Cl

Laser Beam

Properties of the laser plasmaEnergy of the ions : about 100 eV/uEmission 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)

3.35 1012 W/cm2

H. V.

Photo album of the experiment (Okamura RIKEN)

Beam Spec at the end of injector

1s

120Hz

E=1.75MeV/u

1E9 ppp

<I> = 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

12

12

2.0T

(4.2,1.4)

0.75m

4.353 – 5.000m

0.647m

Lattice functions of the booster ring ( radial sector)

Booster (spiral sector)Ncell

k

fpack

Bmax

tune

Long straight

r

excursion

12

12

0.35

57 degree

1.66T

(4.4, 1.3)

1.36m

3.483 – 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 70-400MeV/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

fpack

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

Lattice functions of the main ring

Injection and extraction scheme

booster

main ring

Injector1 turn injection

fast extraction

1 turn injection

massless extraction

Frequency 0.84MHz～ 4.15MHzAcc. voltage 11.0kV （ φ＝ 60°）# of cavities 2Core thickness 30mm# of cores 3/cavity

410mm

Booster(spiral) ring rf cavity parameters

Booster ring core shape

Shunt impedance 151Ω/cavityRF power 25kW/cavityCore weight 310kg/core

Main ring rf cavity parameters

Frequency 6.62MHz～ 7.15MHzAcc. voltage 16.0kV （ φ＝ 60°）# of cavities 2Core thickness 30mm# of cores 3/cavity

410mm

Main ring core shape

Shunt impedance 118.4Ω/cavityRF power 100kW/cavityCore weight ~274kg/core

Power consumption

Preinjector 350kW

Booster magnet 280kW

cavity 50kW

Main ring magnet 800kW

cavity 200kW

total 1680kW

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