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Upgrading of the accelerator facilities at Upgrading of the accelerator facilities at
iThemba Laboratory for Accelerator Based iThemba Laboratory for Accelerator Based
Sciences (iThemba LABS) to increase the Sciences (iThemba LABS) to increase the
production of radionuclidesproduction of radionuclides
Layout of the talk
� Overview of facilities at iThemba LABS which operates a 200 MeV
separated-sector cyclotron and two 8 MeV solid-pole injector
cyclotrons
� A flat-top system for the light-ion injector cyclotron (SPC1)
�An additional buncher for the transfer beam line
�A flat-top system for the separated-sector cyclotron (SSC)
�A new vertical beam line for radionuclide production
� Beam splitting and an additional horizontal beam line for radionuclide
production
�Diagnostic equipment for high-intensity beams:
� Non-destructive beam position monitors
� High intensity 50kW beam stop
Separated-Sector Cyclotron FacilitySeparated-Sector Cyclotron Facility
0 10 20 m
beambeamswingerswinger
SSCSSC
SPC1SPC1SPC2 SPC2
Polarized ion sourcePolarized ion source
ECR ion sourceECR ion source
RadioisotopeRadioisotopeproductionproduction
Neutron therapyNeutron therapy
electronicselectronics electronicselectronics
Proton therapyProton therapy
Nuclear Physics Exp. vaultsNuclear Physics Exp. vaults
Rf-system
Sector Magnet
Rf-system
Low Energy In
High Energy Out
The SSC•4 separate sectors
(SSC)
•Variable-energy
machine
•K = 200 MeV
•RF frequency : 7
to 26 MHz
Solid-pole injector cyclotron 1 (SPC1)•K = 8 MeV
•Internal PIG
ion source
•Radionuclide
production
•Radiotherapy
CYCLOTRON OPERATING SCHEDULE
0.0
0
2.0
0
4.0
0
6.0
0
8.0
0
10
.00
12
.00
14
.00
16
.00
18
.00
20
.00
22
.00
24
.00
M ONDAY
TUESDAY
WEDNESDAY
THURSDAY
FRIDAY
SATURDAY
SUNDAY
Time of day
NEUTRON THERAPY PROTON THERAPY ISOTOPE PRODUCTION NUCLEAR PHYSICS ENERGY CHANGE
CYCLOTRON OPERATING SCHEDULE
-1
0
1
0 60 120 180 240 300 360
Phase (degrees)
Am
plitu
de
main voltage
3th harmonic voltage
flat-top voltage
-1
0
1
0 60 120 180 240 300 360
Phase (degrees)
Am
plitu
de
main voltage
3th harmonic voltage
flat-top voltage
A higher-order harmonic is added to provide a flatter
accelerating voltage for less energy spread, smaller beam
widths and better beam extraction
FLAT-TOPPING SYSTEMS AT iTHEMBA LABS
Without flat-topping
SPC1 BUNCHER SSC18°°°° 12°°°°
320 µA
SPC1 SSC
With flat-topping
45°°°° 25°°°°
� TO IMPROVE BOTH THE BEAM QUALITY AND INTENSITY
OF THE 66 MeV p+ BEAM FOR ISOTOPE PRODUCTION
∼∼∼∼ 400 µµµµA
ADDITIONAL
BUNCHER
h = 2650 µµµµA h = 4
h = 2
BUNCHER
With flat-topping
120µA
99.7% transmission
The flat-top system of SPC1Capacitive
Coupling
Tune the 2nd
resonance of the
“rf cavity” to the
5th harmonic of
the fundamental
frequency
SPC1 SIDE VIEW
f0 = 16.31 MHz
for 66 MeV p+
Main Resonator
Two SPC1 flat-top resonators
Advantages of flat-topping :
•Higher beam intensity
•Better beam quality – less energy spread
(a) Beam orbit pattern with the
5th harmonic flat-top system(b) Beam orbit pattern without
the 5th harmonic flat-top system
S S C w i t h F L A T - T O P P I N G R E S O N A T O R
EEC
POSITION OF
FLAT-TOPPING
RESONATOR
Low energy inLow energy in
INJECTIONINJECTIONEXTRACTIONEXTRACTION
1.1.1.1. lower dee housinglower dee housinglower dee housinglower dee housing 2.2.2.2. acceleration gapacceleration gapacceleration gapacceleration gap 3.3.3.3. top of the upper top of the upper top of the upper top of the upper
deedeedeedee plateplateplateplate 4.4.4.4. beam gapbeam gapbeam gapbeam gap 5.5.5.5. shortshortshortshort----circuit plate at injectioncircuit plate at injectioncircuit plate at injectioncircuit plate at injection 6.6.6.6.
shortshortshortshort----circuit plate at extractioncircuit plate at extractioncircuit plate at extractioncircuit plate at extraction 7.7.7.7. and and and and 8.8.8.8. ports for coupling and ports for coupling and ports for coupling and ports for coupling and
tuningtuningtuningtuning components components components components 9.9.9.9. top of the bottom dee platetop of the bottom dee platetop of the bottom dee platetop of the bottom dee plate 10.10.10.10. plate for plate for plate for plate for
detuningdetuningdetuningdetuning of an unwanted resonance modeof an unwanted resonance modeof an unwanted resonance modeof an unwanted resonance mode....
The 3-D drawing of the SSC flat-top resonator
Installation of the flat-top resonator
Bombardment station for radionuclide production
Thick target radionuclide production
20 20 20 20 555516.016.016.016.061.5 61.5 61.5 61.5 →→→→ 20.020.020.020.0AgAgAgAg103103103103PdPdPdPd
202020201.51.51.51.52.62.62.62.628.6 28.6 28.6 28.6 →→→→ 21.021.021.021.0TlTlTlTl201201201201TlTlTlTl
61.5 61.5 61.5 61.5 →→→→ 25.525.525.525.5
61.5 61.5 61.5 61.5 →→→→ 40.040.040.040.0
62.6 62.6 62.6 62.6 →→→→ 47.647.647.647.6
61.5 61.5 61.5 61.5 →→→→ 39.439.439.439.4
62.6 62.6 62.6 62.6 →→→→ 57.757.757.757.7
34.0 34.0 34.0 34.0 →→→→ 2.42.42.42.4
62.6 62.6 62.6 62.6 →→→→ 39.439.439.439.4
34.3 34.3 34.3 34.3 →→→→ 18.118.118.118.1
60.7 60.7 60.7 60.7 →→→→ 38.738.738.738.7
Energy windowEnergy windowEnergy windowEnergy window
(MeV)(MeV)(MeV)(MeV)
20202020777715.015.015.015.0PrPrPrPr139139139139CeCeCeCe
20202020121212127.07.07.07.0MgMgMgMg22222222NaNaNaNa
2020202066667.07.07.07.0NaINaINaINaI123123123123IIII
2020202099998.68.68.68.6RbClRbClRbClRbCl82828282SrSrSrSr
1515151533331.31.31.31.3RbClRbClRbClRbCl81818181RbRbRbRb
20202020
20202020
4444
4444
5.0 5.0 5.0 5.0
5.05.05.05.0
69696969GaGaGaGa71717171Ga Ga Ga Ga
68686868GeGeGeGe
20202020
20202020
2222
6666
4.44.44.44.4
7.4 7.4 7.4 7.4
ZnZnZnZn
GeGeGeGe
67676767GaGaGaGa
Diameter of Diameter of Diameter of Diameter of
discdiscdiscdisc
(mm)(mm)(mm)(mm)
ThicknessThicknessThicknessThickness
(mm)(mm)(mm)(mm)
MassMassMassMass
(gram)(gram)(gram)(gram)
TargetTargetTargetTargetRadionuclideRadionuclideRadionuclideRadionuclide
3D drawing of the new vertical beam line
1. the horizontal beam line
2. the 90°°°° bending magnet
3. two quadrupole magnets
4. sweeper magnets
5. steerer magnet
6. vacuum chamber for diagnostic
equipment with a Faraday cup,
harp and capacitive probe for
current measurement
7. shielding lift mechanism for
target exchanges
8. 9. and 10. inner iron shield
11. target
12. water tanks with a 4%
ammonium pentaborate solution
13. iron shield
14. borated paraffin-wax shield
15. support structure.
The new vertical beam line for radionuclide production
The planned beam lines for supplying two targets, simultaneously,
with beam for radionuclide production. The main components are the
electrostatic channel EC, the septum magnet SPM, the bending magnet
BM1and the existing switcher magnet SW. The bending magnet BM2
deflects the beam downward into the vertical beam line. Q, SM and D
designate quadrupole magnets, steering magnets and diagnostic
vacuum chambers, respectively.
New beam line with beam splitting for radioisotope
production
Installation of the new high-power beam stop
Non-destructive beam position monitor
Positions at which BPMs have been installed
Beam position display with non-destructive beam position
monitors after automatic alignment at the second monitor
Beam Alignment on x– and y– axes
The scale ranges are from minus to plus 30 mm.
I would like to thank the IAEA for the financial support.
Enkosi, Ngiyabonga, Kea le boga
Thank you !