FFAG Accelerator for Ibaraki Proton Therapy Facility

Takeichiro Yokoi(Div. of Health and Welfare,

Ibaraki Pref.)

Ibaraki Pref. Proton Thetapy Facility

Aim to build a proton therapy facility of the prefr

ectural cancer therapy center 1st step: Proton facility (future option:Proton+ Heavy Ion )

FFAG is to be employed as the accelerator (Collaboration with KEK)

Time Schedule

• 2006 Spring : Facility Planning complete• 2006 Summer: Basic Accelerator Design

complete • 2007 Spring : Facility Design complete

Construction start• 2010 Spring :Commissioning start• 2011 Spring : Test Treatment start

Accelerator Specifications Requirements ….. Particles: Proton(future upgrade:Carbon) Final energy: 230MeV Beam intensity: >100ns(5Gy/min)

FFAG Accelerator High repetition rate(>100Hz) High intensity Easy operation Multi-port extraction(:fast extraction)

Advantages of FFAG accelerator

• High Current(>100nA) cf. Conventional medical synchrotron ~10nA

Flexibly adapted to the development of treatment

• Simultanous Multi-port extraction parallel treatment (to improve opration efficiency) constantly delivered beam line • Pulse beam suited to the spot scanning• ( Upgradability to the heavy ion facility)

Machine Requirements (@FFAG04)

• Maximum field<1.2T(on orbit)• Spiral sector type FFAG• Phase advance/cell~90º• Injector :Linac (H- charge exchange Injection) (energy:7MeV)

Updated Machine Requirements

• Radial sector type FFAG

• Maximum field<1.6T(on orbit)

• Phase advance/cell~90º

• Injector :cyclotron(H+ Injection)

(energy>20MeV)

• Straight section>1m

Parameter Search(Linear Model)Φ=90°

Φ=90°

# sector:16

K~12

θ(F)=θ(D)=4.9°

Rave~6.5m

(@230MeV)

Lattice Parameter(Linear Model)

Phase advance/cell : 91º/60°(H/V)

　 β(@drift space): 2m/2m(H/V)

*No coil space

Parameter Search(Hard-edge Model) (1)

From linear model,…..

(1) #cell=16

(2) phase advance/cell

~100º/60°(H/V)

(3) k=12

(4) Bmax=1.6T

(5) ldrift=0.8m

(6) ravr=6.5m

For Hardedge Model

(1) #cell=16

(2) phase advance/cell

~100º/60°(H/V)

(3) Bmax=1.6T

(4) ldriff=1m, lcoil=0.2m

Parameter Search(Hardedge Model) (2)

K~13

Machine Parameters

Topview of Machine

singlet type magnet

(weight~8t,

simple structure) iron shield

(5cm thick,

supress field leakage)

R~9m: Smaller Ring is now being investigated

Field Distribution

Boundary of F pole

Iron Shield

In the straight section, the remnant field <50gauss

Magnet optimization with tracking is undergoing

Injector cyclotron

Tr 30 Cyclotron

(Advanced Cyclotron System Ltd.)

max intensity: >1000μA

variable energy(15~30MeV)

External beam line(max 9)

Summary Design study of FFAG accelerator for Ibaraki proton th

erapy facility is now undergoing (Design is to be fixed until 2006 summer) Machine parameters …. magnet FDF Radial

# cell 16

k 13

Rep rate 100Hz

Intensity >100nAMagnet optimization using 3D field calculation is undergoingFacility design will be fixed within the next fiscal year.