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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 prefrectural cancer therapy center 1st step: Proton facility
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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 prefrectural 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) *No coil space Phase advance/cell : 91º/60°(H/V) β(@drift space): 2m/2m(H/V)
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
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 Iron Shield Boundary of F pole 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 therapy facility is now undergoing (Design is to be fixed until 2006 summer) • Machine parameters …. • Magnet optimization using 3D field calculation is undergoing • Facility design will be fixed within the next fiscal year.