concept
Design
Injector Cyclotron
for a Medical FFAG
H- compact AIMA cyclotron
M. Conjat, J. Mandrillon,
P. Mandrillon, J. Pasternak
Results
concept
Design
Results
Tentative Layout (according to J.Pasternak)
Preliminary geometry of injection line into
RACCAM FFAG
AIMA cyclotron
(1.75 m diameter)
Septum 0.7 T
6 quads in straights
Design
concept
Results
Concepts….Design Choices
Variable energy-extraction from 7 to 15 MeV
Suitable: 1 energy step corresponds to a 1cm depth step in tissues.
Fast acceleration
Particles reach 15 MeV in 60 turns, well separated.
Simple design
H- acceleration
Multi strippers extraction system with fast switches.
High energy gain per turn
Power is pulsed in order to get a 50 kV peak to peak acceleration voltage,
with 6 gaps/turn.
A single cavity
3 dees galvanically connected, working on the 3rd Harmonic
External High Brightness H- MultiCusp Ion Source
10 mA/cm², 5mA dc (to accelerate 350mA)
concept
Design
Results
Main Characteristics
high brightness multicusp ion source
TYPE OF CYCLOTRON: Negative ion
Size
1.75 diameter
Weight
13 tons
Ion source: H- MultiCusp, external
Extracted Current density (dc)
10 mA/cm²
MAGNET: Closed geometry, 3 sectors
Average field
1.55 tesla
Pole radius
38 cm
Amp turns
52580
RF SYSTEM: 1 single cavity
Number of dees
3
RF voltage
50 kV
RF frequency
70.6 MHz
RF power
~2 kW, pulsed (dc: 2%)
AIMA cyclotron for FDG Production
concept
Design
Results
Extracted beam intensity requirements
Maximum Dose Rate
5 Gray/min
FFAG (100 Hz rep. rate)
2.5 108 proton/cycle,
3 109 proton/cycle needed at injection
With multiturns injection (10t):
3 108 proton/ turn needed at injection
10 turns to fill the FFAG
3 ms (injection F: 3 MHz, 10 revolution time)
With the Cyclotron at 70.6 /3rd Harm:
~200 cyclotron bunches
Cyclotron:
~1.5 107 proton/bunch
Cyclotron DC Current equivalent
170 mA
Requirement at FFAG injection: Energy
Dispersion < 50 keV
Cyclotron DC Current goal:350 mA
concept
Design
Results
About the magnet design
nr & nz versus Radius with ‘EUQUIL’
3D calculation CST,
Compared with measures
B-field Isochronisms versus Radius
with ‘EUQUIL’
nr
nz
concept
Design
Results
About the Dynamic design
Median plane acceleration
Trajectories
& Centers of Curvature
3D electrostatic calculation
& Central region optimization with ‘AGORA’
Energy Gain in gap 6:
90 %
Energy gain in gaps optimization
to accelerate fast.
R (cm)
concept
concept
Design
Results
Variable energy extraction
Energy Focus
Multiple strippers to find
a Cyclotron Energy
Focus
Variable Energy
~7 to ~15 MeV
Strippers
concept
concept
Tracking at Extraction
Envelop at Focus
Design
Results
Normalized Transversal Emittances:
0.5 p mm mrad vertical (worst case)
0.3 p mm mrad horizontal
+ multiple scattering due to stripper traversal
Bunch length in 1st gap: 15°
Extraction Energy - 14 Mev
1 mrad
4 mm
20 mrad
15 mm
Horizontal Envelop (1 s)
0.3 p mm mrad
Vertical Envelop (1 s)
5.3 p mm mrad
Energy spread
75% < 50 KeV
concept
concept
Tracking at Extraction
Envelop at Focus
Design
Results
Normalized Transversal Emittances:
0.5 p mm mrad vertical (worst case)
0.3 p mm mrad horizontal
+ multiple scattering due to stripper traversal
Bunch length in 1st gap: 15°
Extraction Energy - 11 Mev
0.6 mrad
4 mm
30 mrad
20 mm
Horizontal Envelop (1 s)
0.5 p mm mrad
Vertical Envelop (1 s)
7.9 p mm mrad
Energy spread
81% < 50 KeV
concept
concept
Tracking at Extraction
Envelop at Focus
Design
Results
Normalized Transversal Emittances:
0.5 p mm mrad vertical (worst case)
0.3 p mm mrad horizontal
+ multiple scattering due to stripper traversal
Bunch length in 1st gap: 15°
Extraction Energy - 8 Mev
0.4 mrad
4 mm
40 mrad
30 mm
Horizontal Envelop (1 s)
0.50 p mm mrad
Vertical Envelop (1 s)
10 p mm mrad
Energy spread
91% < 50 KeV
concept
Design
Results
Thank you for your attention